Method transfer, partial validation, and cross validation: recommendations for best practices and harmonization from the global bioanalysis consortium harmonization team

This paper presents the recommendations of the Global Bioanalytical Consortium Harmonization Team on method transfer, partial validation, and cross validation. These aspects of bioanalytical method validation, while important, have received little detailed attention in recent years. The team has attempted to define, separate, and describe these related activities, and present practical guidance in how to apply these techniques.

Reduced 123I-BMIPP uptake implies decreased myocardial flow reserve in patients with chronic stable angina

PURPOSE

Long-chain fatty acid (LCFA) is the main energy source for normal myocardium at rest, but in ischemic myocardium, the main energy substrate shifts from LCFA to glucose. 123I-BMIPP is a radiolabeled LCFA analog. In chronic stable angina without previous infarction, we suppose that reduced 123I-BMIPP uptake is related to the substrate shift in myocardium with decreased myocardial flow reserve (MFR). The purpose of this study was to relate 123I-BMIPP uptake to rest myocardial blood flow (MBF), hyperemic MBF, and MFR assessed with 15O-water positron emission tomography (PET).

METHODS

We enrolled 21 patients with chronic stable angina without previous infarction, all of whom underwent 123I-BMIPP single-photon emission computed tomography (SPECT) and 15O-water PET. The left ventricle was divided into 13 segments. In each segment, rest MBF and hyperemic MBF were measured by PET. 123I-BMIPP uptake was evaluated as follows: score 0=normal, 1=slightly decreased uptake, 2=moderately decreased uptake, 3=severely decreased uptake, and 4=complete defect. 123I-BMIPP uptake was compared with rest MBF, hyperemic MBF, and MFR.

RESULTS

The numbers of segments with 123I-BMIPP scores 0, 1, 2, 3, and 4 were 178, 40, 25, 24, and 0, respectively. The rest MBFs for scores 0, 1, 2, and 3 were 0.93+/-0.25, 0.86+/-0.21, 0.97+/-0.30, and 0.99+/-0.37 ml/min/g, respectively. The hyperemic MBFs for scores 0, 1, 2, and 3 were 2.76+/-1.29, 1.84+/-0.74, 1.37+/-0.39, and 1.08+/-0.40 ml/min/g, respectively. The MFRs for scores 0, 1, 2, and 3 were 3.01+/-1.38, 2.20+/-0.95, 1.44+/-0.22, and 1.10+/-0.26, respectively. As 123I-BMIPP uptake declined, hyperemic MBF and MFR decreased.

CONCLUSION

In chronic stable angina without previous infarction, reduced 123I-BMIPP uptake implies decreased MFR.

Sympathetic denervation and reinnervation after the maze procedure

We evaluated serial changes in cardiac sympathetic nerve distribution using 123I-metaiodobenzylguanidine (123I-MIBG) after the Maze procedure. The Maze procedure, in which multiple incisions are made in the atrium, has been concomitantly performed with mitral valve (MV) surgery in an attempt to eliminate atrial fibrillation (AF). Although attenuation of the sinoatrial node response to exercise and a reduction of left ventricular function (left ventricular ejection fraction [LVEF]) in early stages after the Maze procedure have been suggested, factors leading to these changes have not been clarified.

METHODS

Thirteen patients with MV disease were enrolled in this study. Six of them had undergone MV surgery and the Maze procedure (Maze+), and 7 had undergone MV surgery without the Maze procedure (Maze-). All patients underwent cardiac 123I-MIBG imaging preoperatively and 10 d and 1 y after surgery to assess 123I-MIBG uptake (heart-to-mediastinum count ratio of early planar images [H/M]) and the washout rate (WR). Radionuclide ventriculography was also performed to calculate LVEF 3 d after each 123I-MIBG imaging.

RESULTS

The LVEF of the Maze+ group significantly decreased 10 d after surgery (44.2 +/- 4.8; mean +/- SD) compared with that before surgery (60.3 +/- 6.9; P < 0.05) and significantly increased at 1 y (65.2 +/- 2.9) compared with that at 10 d (P < 0.05). In the Maze- group, there was no significant change 10 d (53.0 +/- 12.3) and 1 y (58.6 +/- 4.8) after surgery compared with that before surgery (60.4 +/- 4.6) (P = not significant, each). In the Maze+ group, the H/M (1.51 +/- 0.18) was significantly lower at 10 d after than that at the preoperative stage (1.90 +/- 0.25; P < 0.05) but significantly recovered at 1 y (2.23 +/- 0.18; P < 0.05) with a similar transient increase in the WR (36.7% +/- 6.1% at preoperative stage; 46.9% +/- 3.4% at 10 d; 39.9% +/- 6.5% at 1 y; P < 0.05, each). On the other hand, the Maze- group did not show a significant change in the H/M (1.94 +/- 0.32, 2.06 +/- 0.18, and 2.13 +/- 0.17, respectively; P = not significant, each) but did exhibit a significant decrease in the WR (40.4% +/- 5.1%, 37.0% +/- 5.1%, and 32.9% +/- 2.5%, respectively; P < 0.05, each). Changes in the H/M of both groups significantly correlated with the change in LVEF (r = 0.82; P < 0.05), and the WR showed a significant inverse correlation with changes in the LVEF (r = -0.81; P < 0.05).

CONCLUSION

Cardiac sympathetic nerves were denervated at early stage and reinnervated at late stage after the Maze procedure. Such adrenergic nerve changes may be correlated, at least in part, with changes in left ventricular function after this procedure.

Quantitative analysis of myocardial glucose utilization in patients with left ventricular dysfunction by means of 18F-FDG dynamic positron tomography and three-compartment analysis

PURPOSE

Myocardial glucose utilization (MGU) is altered in various heart diseases. The aim of this study was to quantitatively assess regional myocardial glucose utilization in patients with left ventricular (LV) dysfunction by dynamic( 18)F-fluorodeoxyglucose positron emission tomography (FDG PET).

METHODS

A total of 18 subjects were studied, including ten with LV dysfunction (seven with idiopathic dilated cardiomyopathy and three with aortic regurgitation; NYHA II in 8 and III in 2) and eight healthy normal volunteers. Patients with diabetes mellitus were excluded. A dynamic PET study was performed for 40 min following the injection of 370 MBq of FDG after 50-g glucose loading. On the basis of a three-compartment model, MGU, K1, k2, and k3 were computed on a pixel by pixel basis to generate LV myocardial parametric maps. FDG standardized uptake value (SUV) was also calculated using static images obtained 40 min after FDG injection. These metabolic values were compared with myocardial flow distribution (%Flow), LVEF, LV volumes, and LV wall thickening (WT) determined by gated myocardial single-photon emission computed tomography using QGS software in eight myocardial segments.

RESULTS

MGU correlated positively with LV volumes and negatively with LVEF. K(1) was significantly higher in the segments of the patients than in those of the normal volunteers (0.082+/-0.055 vs 0.041+/-0.017 ml min(-1) g(-1), p<0.05), although there was no difference in MGU between the groups. On the other hand, SUV, k2, and k3 did not differ significantly between the groups. Among the patients, the K1 values were significantly higher in the areas with impaired WT (%WT<17%) (0.109+/-0.063 vs 0.069+/-0.062 ml min(-1) g(-1), p<0.05) and in the areas with flow reduction (%Flow<71%) (0.112+/-0.076 vs 0.071+/-0.046 ml min(-1) g(-1), p<0.05).

CONCLUSION

These results indicate that glucose utilization was preserved in the patients with LV dysfunction, mainly due to an increase in glucose transport, particularly in the regions with severely impaired LV function. Thus, the quantitative assessment of myocardial glucose utilization by FDG dynamic PET may provide useful information for assessing the regional myocardial metabolic status in patients with LV dysfunction.

Serial changes in BMIPP uptake in relation to thallium uptake in the rat myocardium after ischaemia

Several clinical studies have shown that iodine-123 labelled 15-(p-iodophenyl)-3-(R, S)-methylpentadecanoic acid (BMIPP) uptake is often lower than the uptake of perfusion tracers in patients with ischaemic heart disease. However, BMIPP accumulation may not decrease during the acute phase of a stunned myocardium in patients with acute coronary syndrome. We evaluated serial changes in BMIPP and perfusion tracer uptake in the myocardium after ischaemia. We performed a 20-min left coronary artery occlusion followed by reperfusion in male Wistar rats. One hour after the reperfusion, echocardiography was performed. Intravenous injection of iodine-125 labelled BMIPP and thallium-201 was performed 1 day (acute group) and 5 days (subacute group) after the operation. To determine the myocardial distribution of 125I-BMIPP and 201Tl, dual-tracer autoradiography was conducted. We identified regions of interest in the anterolateral wall as an area at risk and in the inferoseptum as a remote control area. The anterolateral wall/inferoseptum ratio (A/I ratio) was calculated to compare the distributions of 125I-BMIPP and 201Tl. Coronary occlusion induced hypokinesia in the anterolateral region 1 h after the reperfusion. The A/I ratio of 125I-BMIPP was significantly higher than that of 201Tl in the acute group (1.01 +/- 0.15 vs 0.80 +/- 0.23, P<0.001). On the other hand, there was no significant difference between the A/I ratios of 125I-BMIPP and 201Tl in the subacute group (0.88 +/- 0.18 vs 0.85 +/- 0.18). Two rats showed a significantly lower A/I ratio of 125I-BMIPP than 201Tl in the subacute phase. These data suggest that BMIPP uptake is preserved despite a decrease in perfusion in the acute phase after ischaemia. In the subacute phase, on the other hand, BMIPP uptake is similar to or even lower than thallium uptake. Since BMIPP uptake may change with time after ischaemia, careful interpretation of BMIPP uptake after ischaemia is required in a clinical setting.

Quantitative gated myocardial perfusion single photon emission computed tomography improves the prediction of regional functional recovery in akinetic areas after coronary bypass surgery: useful tool for evaluation of myocardial viability

OBJECTIVE

Assessment of myocardial viability in akinetic areas is essential in surgery for ischemic heart disease, including coronary artery bypass grafting and left ventriculoplasty. The aim of this study is to evaluate the utility of quantitative indices of perfusion uptake, wall motion, and wall thickening of each region calculated by quantitative electrocardiogram-gated single photon emission computed tomography (SPECT) for prediction of functional recovery after coronary artery bypass grafting.

METHODS

Forty patients scheduled for coronary artery bypass grafting were prospectively included. Electrocardiogram-gated SPECT was performed before and 1 week and 3 months after operation, and coronary angiography was performed before and after operation. The myocardium was divided into 9 segments and myocardial viability, assessed by improvement of the wall motion score using a cine mode display, and evaluated by radionuclide criteria (perfusion uptake, wall motion, wall thickening). Twenty-four segments with moderate hypokinesis and 14 segments with akinesis with patent grafts were assessed.

RESULTS

All segments with moderate hypokinesis except 1 (96%) had improved wall motion scores postoperatively, whereas of 14 segments with akinesis only 7 segments (50%) had improved wall motion scores. The preoperative perfusion uptake in the improved segments was significantly higher than in the nonimproved segments (62.7% +/- 15.6% vs 46.4% +/- 24.5%, P =.01). There was a significant difference in wall motion between the improved and nonimproved segments (3.8 +/- 2.2 mm vs 1.4 +/- 1.4 mm, P =.001), and the preoperative wall thickening of the improved segments was significantly higher than in the nonimproved segments (27.2% +/- 14.1% vs 8.2% +/- 10.3%, P <.0001). The optimal cutoff level of perfusion uptake was 50%, with the highest accuracy of 72%, and the optimal cutoff levels of wall thickening and wall motion were 10% and 1.5 mm, with the highest accuracies of 76% and 85%, respectively.

CONCLUSION

The regional functional index calculated by electrocardiogram-gated SPECT indicated that wall thickening was well correlated with functional recovery compared with wall motion or perfusion uptake. This suggests that the wall thickening calculated by electrocardiogram-gated SPECT may be more useful to predict functional recovery than regional myocardial perfusion. Or, it could suggest that in addition to perfusion uptake, wall thickening could enhance the objective assessment of myocardial viability.

Prediction of functional recovery after coronary bypass surgery using quantitative gated myocardial perfusion SPECT

Previous studies have demonstrated that myocardial perfusion imaging using 99mTc-tetrofosmin at rest allows viability assessment similar to that obtained with 201Tl imaging and 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET). The simultaneous assessment of perfusion and regional function is now available by quantitative gated myocardial perfusion single-photon emission computed tomography (SPECT). This study was designed to evaluate the utility of quantitative values of wall motion and wall thickening, calculated by quantitative gated myocardial perfusion SPECT, for the prediction of functional recovery after coronary bypass grafting (CABG). Fifty-six patients with coronary artery disease scheduled for CABG were included prospectively. All patients underwent 99mTc-tetrofosmin gated SPECT imaging at rest preoperatively and 3 months after CABG. The myocardium was divided into nine segments and the average quantitative values of regional perfusion (percentage uptake) (%), wall motion (mm) and wall thickening (%) were determined automatically using quantitative gated SPECT (QGS) software. The wall motion score was defined visually using a four-point scale (0, normal; 3, akinesis), and segments with severe asynergy (score of 2 or 3) with patent grafts were assessed. Of 77 segments with severe asynergy, 56 segments showed improved wall motion and 21 segments did not improve after CABG. The area under the receiver operating characteristic curve of wall thickening for the prediction of functional recovery was significantly higher (0.92) than that of the percentage uptake (0.77, P<0.017) or wall motion (0.60, P<0.0001). When each analysis used the optimal threshold, the wall thickening analysis (>or=10%) had a sensitivity of 95% and a specificity of 81%. These values tended to be higher than those of the percentage uptake (sensitivity, 86%; specificity, 67%). The wall motion analysis (>or=1.5 mm) had a significantly lower sensitivity of 75% and specificity of 43% than the wall thickening analysis (P=0.0038 and P=0.011, respectively). The results indicate that wall thickening, calculated by QGS software, may be more useful than regional perfusion or wall motion analysis for the prediction of functional recovery after CABG. The areas of asynergy with relatively preserved wall thickening may have the potential for improved function despite severely decreased perfusion.

Insulin-like growth factor-I enhances choleretic action of FK506 in rats

FK506 is an immunosuppressant for organ transplantation in the same clinical settings as cyclosporine (CsA). In the management of liver transplantation, FK506 has advantages over CsA, in terms of rejection and corticosteroid requirements. Recent clinical findings in liver transplant patients indicate that FK506, but not CsA, stimulates choleresis, suggesting that FK506 treatment may accelerate recovery from cholestatic dysfunction through its choleretic action. Recently, we demonstrated in rats that exogenous treatment with insulin-like growth factor I (IGF-I) results in an increase in bile flow and also that FK506 has the potential to increase hepatic production of IGF-I. However, circulating levels of IGF-I in FK506-treated rats were only 30% higher than in nontreated rats. In this study, we evaluated the combined effect of treatment with both IGF-I and FK506 on bile flow in rats to explore the possibility that combination treatment in liver transplant patients could enhance the choleretic action of FK506, benefiting the transplanted liver. Combination treatment of IGF-I with FK506 resulted in a potent and long-lasting increase in bile flow. Overall, this study demonstrated that IGF-I treatment enhanced the choleretic action of FK506, providing potential clinical utility for combination therapy using these two drugs, in treatment after liver transplantation.

Transient left ventricular dysfunction in ischaemic myocardium after stress: comparative study with exercise and pharmacological stress gated myocardial single photon emission computed tomography

In ischaemic heart disease patients, transient left ventricular dysfunction is observed due to post-exercise stunning. The aim of this study was to determine whether transient left ventricular dysfunction could also be seen after short-acting pharmacological stress (adenosine triphosphate). A 1 day rest/stress gated myocardial single photon emission computed tomography was performed on 362 patients suspected of having ischaemic heart disease by exercise (n=199) or short-acting pharmacological stress (n=163). Left ventricular ejection fraction were estimated both at rest and stress. Based on perfusion findings, patients were subdivided into ischaemia, fixed defect and normal group. For the ischaemia and fixed defect group, left ventricular ejection fraction after stress was significantly decreased compared with the resting value by exercise stress (ischaemia group, 57.5+/-11.0 vs 60.4+/-10.4; fixed defect group, 47.7+/-16.7 vs 49.6+/-16.8; P<0.01), but not by pharmacological stress (ischaemia group, 55.8+/-13.4 vs 57.1+/-13.8; fixed defect group, 50.8+/-13.5 vs 50.6+/-13.1; P=NS). In the normal group, left ventricular ejection fraction after stress was not significantly changed by either exercise (65.7+/-10.4 vs 66.8+/-10.2; P=NS) or pharmacological stress (63.0+/-11.7 vs 64.0+/-12.1; P=NS). It is concluded that a transient decrease in left ventricular ejection fraction after stress was observed following post-exercise, not following a short-acting pharmacological stress in patients showing perfusion abnormalities. Transient left ventricular dysfunction may be the result of post-exercise stunning, not from subendocardial hypoperfusion induced by short-acting pharmacological stress.

Altered myocardial flow reserve and endothelial function late after Kawasaki disease

OBJECTIVES

Coronary arterial lesions after Kawasaki disease (KD) may cause coronary endothelial dysfunction as the result of intimal hypertrophy. Our purpose was to assess myocardial flow reserve (MFR) and endothelial function in various myocardial regions after KD by using positron emission tomography.

STUDY DESIGN

Twenty-seven patients, 17.2 +/- 3.2 years of age, who had KD at 1.9 +/- 1.4 years, and 12 normal healthy subjects, 26.5 +/- 3.4 years of age, were evaluated by means of myocardial blood flow (MBF) with (15)O-water positron emission tomography. MFR was estimated by MBF changes under adenosine triphosphate infusion and endothelial function by MBF changes under cold pressor testing. The left ventricle was divided into three coronary territories. Ten stenotic regions, 20 aneurysmal regions, 30 regressed aneurysmal regions, and 21 regions without coronary arterial lesions were compared with 36 control regions of the normal volunteers.

RESULTS

MBF at rest was similar in each region. Hyperemic blood flow and MFR in each region after KD was significantly lower than those in the regions of normal volunteers. MBF during cold pressor testing was significantly reduced in each region after KD, as compared with no change in the control regions.

CONCLUSIONS

Our study indicates impaired MFR and endothelial function regardless of coronary artery status after KD.

Value and limitation of myocardial fluorodeoxyglucose single photon emission computed tomography using ultra-high energy collimators for assessing myocardial viability

Single photon emission computed tomography (SPECT) using ultra-high energy collimators permits wide clinical application of (18)F-fluorodeoxyglucose (FDG) imaging without the use of expensive positron emission tomography (PET) cameras. This study was designed to evaluate the value of FDG SPECT using ultra-high energy collimators in assessing myocardial viability compared with FDG PET on a regional basis. We prospectively studied 33 patients with ischaemic heart disease. The patients were injected with 555 MBq of FDG under a hyperinsulinaemic glucose clamp, and FDG PET was performed 40 min later. FDG SPECT using ultra-high energy collimators was performed immediately after FDG PET. The images of the left ventricular myocardium were divided into nine segments and the regional defect score was assessed visually using a four-point scale (0=normal to 3=defect). Regional FDG uptake (%uptake) was quantitatively analysed using polar maps. In 297 segments of all the 33 patients, agreement between the defect scores based on FDG SPECT images and those based on FDG PET images was 70%, and agreement within one rank was 96% (kappa value=0.52). The %uptake based on FDG SPECT images significantly correlated with that based on FDG PET images (r=0.77, P<0.01). However, the defect scores in the inferior wall based on FDG SPECT images were higher (1.41+/-1.14) than those based on FDG PET images (1.06+/-1.12, P<0.01). When the viable region is defined as %uptake > or =50% in FDG PET studies, the optimal cut-off level of %uptake based on FDG SPECT images was 60% in the anterior wall, apex, septum and lateral wall (accuracies, 97%, 93%, 96% and 99%, respectively), and 45% in the inferior wall (accuracy, 99%). It is concluded that FDG SPECT using ultra-high energy collimators can be used for the assessment of myocardial viability as accurately as FDG PET. However, a slight difference was observed in the defect scores mainly due to attenuation in the inferior wall. Therefore, a slightly different cut-off level for assessing myocardial viability should be applied to the inferior wall when using FDG SPECT.

Validation of left ventricular function from gated single photon computed emission tomography by using a scintillator-photodiode camera: a dynamic myocardial phantom study

A scintillator-photodiode camera is able to acquire single photon emission computed tomography (SPECT) images by using a rotating chair system. We validated the left ventricular (LV) parameters of this camera system utilizing a dynamic myocardial phantom. Gated myocardial SPECT of a dynamic myocardial phantom (Hokkaido University type; end diastolic volume (EDV), 143 ml; end systolic volume (ESV), 107 ml; ejection fraction (EF), 25%) was performed with this scintillation camera. LV parameters were calculated using pre-installed software (Mirage Myocardial Perfusion SPECT) (study 1) and the other software (QGS; Cedars-Sinai) (study 2). For comparison, SPECT from a traditional Anger camera were processed by the QGS software (study 3). The estimated volumes were similar among the three studies (EDV, 110+/-8 ml in study 1, 112+/-2 ml in study 2 and 111+/-1 ml in study 3; ESV, 86+/-8 ml in study 1, 93+/-4 ml in study 2 and 91+/-2 ml in study 3). The estimated EFs were 23+/-3%, 17+/-2%, and 18+/-1%, respectively. The calculated volume within each study was underestimated by approximately the same degree. However, each estimated EF value for each study was close to the actual value. The estimated LV function using the scintillator-photodiode camera system may be considered as a suitable alternative to the traditional Anger camera system.

Assessment of coronary function in children with a history of Kawasaki disease using (15)O-water positron emission tomography

BACKGROUND

Coronary abnormalities after Kawasaki disease (KD) may be associated with endothelial dysfunction due to intimal hypertrophy. The purpose of this study was to evaluate myocardial flow reserve (MFR) and endothelial function in regressed aneurysmal regions after KD. Methods and Results- Subjects were 12 patients aged 16.0+/-2.6 years who suffered from KD at 1.7+/-1.5 years and 12 normal subjects aged 26.5+/-3.4 years. MFR and endothelial function were estimated, respectively, by changes in myocardial blood flow (MBF) during ATP infusion and by that during cold pressor test using (15)O-water positron emission tomography. Data from 24 regressed aneurysmal regions were compared with those from the corresponding regions (n=36) in the control group. Although the MBF at rest in the regressed aneurysmal regions was similar to that in controls, the MBF at a hyperemic state induced by ATP infusion in the regressed aneurysmal regions was significantly lower than that in the control regions. Therefore, the MFR in regressed aneurysmal regions was significantly lower than that in controls (3.53+/-0.95 versus 4.60+/-1.14; P<0.05). MBF at rest and during the cold pressor test did not change in the control regions, but it was significantly reduced in regressed aneurysmal regions. The ratio of MBF during the cold pressor test to MBF at rest was significantly lower in regressed aneurysmal regions than in control regions (0.67+/-0.15 versus 1.00+/-0.15; P<0.05).

CONCLUSIONS

MFR and endothelial function are often impaired in regressed aneurysmal regions after KD, and tomography enables the noninvasive evaluation of coronary function.

Accuracy and reproducibility of left ventricular function from quantitative, gated, single photon emission computed tomography using dynamic myocardial phantoms: effect of pre-reconstruction filters

We have investigated the accuracy and reproducibility of left ventricular (LV) functions using quantitative, gated, single photon emission computed tomography (SPECT) software dependent on critical frequencies of pre-reconstruction filters. This study incorporated dynamic myocardial phantoms (myocardial and cone shapes). Gated SPECT of 8-interval sets were pre-filtered with Butterworth filters (critical frequency varying between 0.16 and 1.16 cycles/cm, order 5) and with no filter. Phantoms were repositioned, and SPECT acquisitions were repeated. As the critical frequency increased, the estimated LV volume increased to reach a plateau at the level of the critical frequency, 0.54 cycles/cm. Conversely, the values of ejection fractions, wall motion and wall thickening with different filters which used critical frequency of > or =0.39 cycles/cm remained unchanged. However, LV functions and volumes were underestimated when any pre-reconstruction filter was used. Standard deviations of LV functions after repeated measurements were unaffected by different filters with critical frequencies of > or =0.39 cycles/cm. Standard deviations of LV volume, ejection fraction, wall motion and wall thickening were <2.2 ml, <0.9%, <0.6 mm and <8.7%, respectively. Therefore, with the exception of low critical frequencies, LV functions and volumes were highly reproducible when these routine reconstruction filters were used.

Processing and mechanical properties of autogenous titanium implant materials

Pure titanium and some of its alloys are currently considered as the most attractive metallic materials for biomedical applications due to their excellent mechanical properties, corrosion resistance, and biocompatibility. It has been demonstrated that titanium and titanium alloys are well accepted by human tissues as compared to other metals such as SUS316L stainless steel and Co-Cr-Mo type alloy. In the present study, highly porous titanium foams with porosities <or=80% are produced by using a novel powder metallurgical process, which includes the adding of the selected spacers into the starting powders. The optimal process parameters are investigated. The porous titanium foams are characterized by using optical microscopy and scanning electron microscopy. The distribution of the pore size is measured by quantitative image analyses. The mechanical properties are investigated by compressive tests. This open-cellular titanium foams, with the pore size of 200-500 microm are expected to be a very promising biomaterial candidates for bone implants because its porous structure permits the ingrowths of new-bone tissues and the transport of body fluids.

High-speed plasmid isolation using 96-well, size-exclusion filter plates

The accelerating pace of genomics analysis has necessitated the abbreviation of DNA sample preparation protocols. We have developed a size-exclusion-based system for the rapid isolation ofplasmid DNA in a 96-well microplate format. This high-speed protocol employs a modified alkaline lysis methodfor the preparation of the bacterial lysate, followed by three short vacuum filtration steps. Unlike traditional bind/wash/elute methods, there is no need to use chaotropic salts or ethanol. The samples are recovered from the top side of the MultiScreen96 PLASMID plates. Starting with bacterial cell pellets, the entire prycedure for purifying the plasmid DNA can be performed in 30 min with a multichannel pipettor. The high yields, reproducibility, and quality of the plasmids make this system a good choice for any cloning or DNA sequencing operation.

Induction of choleresis by immunosuppressant FK506 through stimulation of insulin-like growth factor-I production in the liver of rats

FK506 (Tacrolimus) is an effective immunosuppressant currently used worldwide in organ transplantation. Based on our recent findings that insulin-like growth factor-I (IGF-I) is important for the stimulation of choleresis in vivo, in this study we investigated the effect of FK506 on bile flow and the plasma and hepatic levels of IGF-I in rats. Intravenous treatment of rats with FK506 resulted in a significant increase in bile flow, whereas cyclosporin A induced a significant decrease. A significant increase in plasma levels of IGF-I was observed in rats 30 min after a single intravenous administration of FK506. Oral treatment of rats with FK506 for 1 week also resulted in an increase in both plasma and hepatic levels of IGF-I. Overall, this study showed that FK506 treatment increased bile flow and also induced an increase in the plasma and hepatic levels of IGF-I in rats, suggesting that a stimulation of hepatic IGF-I production by FK506 may contribute to its choleretic profile.

Induction of bone loss by bile duct ligation in rats

Metabolic bone loss is the most common complication of chronic liver disease. However, there is little information available about bone loss in rats with a ligated bile duct, a biliary-type of experimental cirrhosis model. Therefore, in this study, the effect of bile duct ligation (BDL) on bone mineral density (BMD) and plasma insulin-like growth factor-I (IGF-I) levels was examined in rats. Two weeks after BDL operation, the rats with a ligated bile duct showed a pronounced and significant decrease in both trabecular and cortical BMD of the femur. In these rats, decreases in food intake and plasma IGF-I levels plus elevated levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase and bilirubin were also observed. When the effect of dietary restriction (30% or 50%) over 2 weeks was then investigated in normal rats, 50% food restriction resulted in a significant decrease in femoral trabecular bone density although BMD was unchanged by 30% dietary restriction. The plasma levels of IGF-I were also decreased in food-restricted rats. Thus, the decrease in femoral bone density in 50% food-restricted rats was less potent compared with BDL rats; nevertheless, the decrease in plasma levels of IGF-I was almost equally potent in both BDL and food-restricted rats. Overall, this study showed that BDL operation resulted in a pronounced bone loss in rats, but also that this bone loss might not be merely due to the decreases in food intake and plasma IGF-I levels. These results suggest that BDL in rats is a useful experimental cirrhosis model for evaluating the bone loss associated with chronic liver disease.

Purkinje cells in the adult cat cerebellar cortex possess a perineuronal net of proteoglycans

The Purkinje cells in the adult cat cerebellar cortex were found to possess perineuronal proteoglycans which could be stained with our fine cationic iron colloid and Fujita's highly concentrated aldehyde fuchsin, and digested by chondroitinase ABC/keratanase/ heparitinase and hyaluronidase. The Purkinje cells are surrounded by some collagenous elements which are stained with Gömöri's ammoniacal silver and digested by collagenase. The Purkinje cells also express nerve cell surface glycoproteins which are labeled with lectin Vicia villosa agglutinin and digested by a double treatment with collagenase and endo-alpha-N-acetylgalactosaminidase. Sole digestion by endo-alpha-N-acetylgalactosaminidase never erased the lectin labeling of the nerve cell surface glycoproteins. These findings suggest that the collagenous elements mediate the linkage of the perineuronal proteoglycans to the nerve cell surface glycoproteins. It is presumed that in mice and rats, the perineuronal nets of proteoglycans and nerve cell surface glycoproteins of the Purkinje cells are so thin or coarse that they can not be sufficiently visualized under the light microscope.

Comparison of (18)F-FDG, (131)I-Na, and (201)Tl in diagnosis of recurrent or metastatic thyroid carcinoma

There are several reports about the usefulness of (18)F-FDG PET in thyroid cancer. However, few studies have compared FDG PET with (131)I and (201)Tl scintigraphy. The aim of this study was to evaluate the clinical significance of whole-body FDG PET in differentiated thyroid cancer and to compare the results with those obtained from (131)I and (201)Tl scintigraphy.

METHODS

Whole-body FDG PET was performed on 32 patients (10 men, 22 women; age range, 30-77 y; mean age, 54 y) with differentiated thyroid cancer (5 cases of follicular cancer and 27 of papillary cancer) after total thyroidectomy. An overall clinical evaluation was performed, including cytology, thyroglobulin level, sonography, MRI, and CT, to allow a comparison with functional imaging results for each patient. Metastatic regions were divided into five areas: neck, lung, mediastinum, bone, and other. Multiple lesions in one area were defined as one lesion. The tumor-to-background ratio (TBR) was measured for the lesions that were positive for both (201)Tl uptake and FDG PET uptake.

RESULTS

The number of lesions totaled 47. Forty-one (87%) were detected by all scintigraphic methods. FDG uptake was concordant with (131)I uptake in only 18 lesions (38%). FDG uptake was concordant with (201)Tl uptake in 44 lesions (94%). Only one lesion was negative for FDG uptake and positive for (201)Tl uptake, and two lesions were positive for FDG uptake and negative for (201)Tl uptake. A significant correlation was seen between the TBR of (201)Tl and that of FDG (r = 0.69; P<0.05).

CONCLUSION

These data indicate that for detecting metastatic lesions, FDG PET and (131)I scintigraphy may provide complementary information, whereas FDG PET may provide results similar to those of (201)Tl scintigraphy. Thus, the combination of (131)I scintigraphy and FDG PET (or (201)Tl scintigraphy) is the method of choice for detecting metastatic thyroid cancer after total thyroidectomy.

Lesser reduction in bone mineral density by the immunosuppressant, FK506, compared with cyclosporine in rats

BACKGROUND

Posttransplantation osteopenia leading to osteoporosis induced commonly by treatment with immunosuppressants including cyclosporine (CsA) is a severe complication and results in lowering the quality of life in patients receiving organ transplantation. FK506 is a newly developed immunosuppressant and is currently being used for the prevention of rejection after organ transplantation. In this study, to investigate whether FK506 as well as CsA would cause osteopenia or not, we evaluated the effect of FK506 on bone mineral density and several parameters relevant to bone metabolism in comparison with that of CsA using normal rats.

METHODS

Ten-week-old male Sprague-Dawley rats were treated with FK506 (vehicle, 1 mg/kg, and 3.2 mg/kg) or CsA (vehicle, 10 mg/kg, and 32 mg/kg) by daily oral gavage for 28 days. Bone mineral density of the femur, plasma insulin-like growth factor I (IGF-I), and urinary deoxypyridinoline were determined by peripheral quantitative computerized tomography, radioimmunoassay, and enzyme-linked immunosorbent assay, respectively.

RESULTS

The reduction in bone mineral density of the femur was observed in both FK506- and CsA-treated rats. The reduction in CsA-treated rats, however, was statistically significant and strikingly severe, whereas that in FK506-treated rats was much less severe than CsA. Plasma IGF-I levels were significantly elevated in FK506-treated rats but not in CsAtreated rats. Urinary deoxypyridinoline levels were unchanged in FK506-treated rats but elevated in CsA-treated rats.

CONCLUSIONS

Compared with CsA, FK506 does not appear to induce severe osteopenia by high-turnover bone metabolism in the rat by mediating via IGF-I induction in part. The results suggest that FK506 may exert favorable effects on bone metabolism in patients with organ transplantation compared with CsA. To assess this idea, further clinical investigations focused on bone metabolism will be required.

Stimulation of choleresis by insulin-like growth factor-I in rats

Insulin-like growth factor-I (IGF-I) is an endogenous growth factor which is mainly produced in the liver. The functions of IGF-I can be summarized as growth-promoting and insulin-like metabolic actions. In the present study, the effect of IGF-I on bile flow and bile acid secretion was investigated in rats. In normal rats bile flow was significantly increased by single exogenous administration of IGF-I, and by 1 week treatment of IGF-I, both bile flow and bile acid secretion were significantly increased. Moreover, to further understand the relationship between IGF-I and bile acid secretion, hypophysectomized rats were next used. We found that the decreases in bile flow and bile acid secretion observed in rats after hypophysectomy, as well as the decrease in the endogenous level of IGF-I in the blood, were partially reversed by 1 week exogenous IGF-I treatment. Overall, this study showed that IGF-I stimulates choleresis associated with an elevation of bile acid secretion in both normal and hypophysectomized rats when exogenously administered, suggesting the importance of IGF-I in the stimulation of choleresis in vivo.

Immobilon-Ny+ nucleic acid blotting membrane: an advanced nylon membrane optimized for superior fixation and reprobing

The use of charged nylon membranes in nucleic acid blotting applications has become an important factor in the success of hybridization-based assays. Retention of nucleic acids on these membranes is promoted by baking at 80 degrees C under vacuum or by exposure to short wavelength UV light, with the latter method preferred. Immobilon-Ny+ is an advanced, positively charged nylon membrane that has been optimized to show superior retention of target DNA and RNA under hybridization conditions. Higher signal levels are obtained in these assays compared to competitive membranes, even after 13 cycles of probing. This report illustrates the superior performance of Immobilon-Ny+ in 32P and chemiluminescent hybridization assays on blotted DNA and RNA.

[Visualization of normal organs in whole-body FDG-PET imaging]

It is important to know FDG accumulation in the normal distributions for interpreting whole-body PET imaging for tumor detection. Twenty-eight normal subjects were studied with whole-body PET imaging and were examined the intensity of FDG uptake in major organs and the factors which caused it's variety. Emission images were acquired and images were reconstructed without attenuation correction. The intensity of FDG uptake was classified into 4 grades visually. No accumulation was found in the thyroid, the esophagus and the spleen. The oral cavity, the liver, the stomach, and the colon were visualized in all subjects. The laryngeal muscle, the cervical muscle, and the heart accumulated FDG with various grade from 1 to 4 grades. No association was found between the intensity of uptake in the organs and volunteer's age. The fasting time was shorter in volunteers whose heart showed "high" grade than those showed less accumulation (p < 0.05). Serum concentration of free fatty acid was significantly lower in them, too (p < 0.05). Various FDG uptake was observed in many organs, especially the laryngeal muscle, the cervical muscle, and the heart. In our study, there was no facter which caused FDG uptake in organs except for the fasting time and the value of free fatty acid in the heart. Such analysis of whole-body FDG distributions in the normal subjects is valuable for tumor detection with FDG-PET.

Determination of imidapril and imidaprilat in human plasma by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry

A sensitive and specific assay of imidapril and its active metabolite, imidaprilat, in human plasma has been developed. This method is based on rapid isolation and high-performance liquid chromatography (HPLC)-electrospray ionization (ESI)-tandem mass spectrometry (MS-MS). Imidapril and imidaprilat were isolated from human plasma using OASIS HLB (solid-phase extraction cartridge), after deproteinization. The eluent from the cartridge was evaporated to dryness, and the residue was reconstituted in mobile phase and injected into the HPLC-ESI-MS-MS system. Each compound was separated on a semi-micro ODS column in acetonitrile-0.05% (v/v) formic acid (1:3, v/v). The selected ion monitoring using precursor-->product ion combinations of m/z 406-->234 and 378-->206, was used for determination of imidapril and imidaprilat, respectively. The linearity was confirmed in the concentration range of 0.2 to 50 ng/ml in human plasma, and the precision of this assay, expressed as a relative standard deviation, was less than 13.2% over the entire concentration range with adequate assay accuracy. The HPLC-ESI-MS-MS method correlates well with the radioimmunoassay method, therefore, it is useful for the determination of imidapril and imidaprilat with sufficient sensitivity and specificity in clinical studies.

Coexistence of rare arteries in the human celiaco-mesenteric system

Some rare anomalies of the celiaco-mesenteric system were observed postmortem in a Japanese adult male: a) The left gastric, common hepatic, splenic and superior mesenteric arteries arose independently from the abdominal aorta. b) The anterior inferior pancreaticoduodenal artery of the superior mesenteric artery issued a hepatic artery which ascended along the anterior surface of the pancreas and gave off the right gastroepiploic, right gastric and cystic arteries. c) The common hepatic artery gave off an anastomosing branch to the superior mesenteric artery. d) The left gastric artery gave off the left accessory hepatic artery. e) The splenic artery issued the accessory middle colic artery. f) The left inferior phrenic artery gave off the esophageal branch. These anomalies are discussed in light of a typological system which we proposed in a previous paper for the celiaco-mesenteric system.

Effects of phenobarbital on aniline metabolism in primary liver cell culture of rats with ethionine-induced liver disorder

In experiment 1, the amount of aniline (AN) metabolites in the primary cell culture medium of the liver cells obtained from ethionine (ET)-treated rats was compared with that of the control (normal) rats. Although the metabolites detected in both groups were p-aminophenol (p-AP), N-acetyl-p-AP (AAP), acetoanilide (AAN), AAP-glucuronide (AAPG), phenylhydroxylamine sulfate (PHAS) and p-AP-glucuronide (p-APG), the amount of AAP was lower and that of p-APG was markedly higher in the ET-treated rats than in the control rats. In experiment 2, phenobarbital (PB) was orally administered to the ET-treated and control rats at a dose of 100 mg/kg. The time course changes in AN metabolites in the primary cell culture medium of liver cells obtained at 2 or 48 hr after PB treatment were compared with those without PB treatment. In the ET-treated rats, the amount of PHAS was slightly higher at 2 hr after PB treatment, and that of AAP was lower and that of p-APG was higher at 48 hr after PB treatment as compared with those without PB treatment. In the control rats, the amounts of AAP, AAN, p-AP and p-APG at 2 hr after PB treatment remained lower than those without PB treatment, and that of AAP was markedly lower and that of p-APG was higher at 48 hr after PB treatment as compared with those without PB treatment. These findings indicated greater detoxication in the primary liver cell culture in the ET-treated rats than in the control rats. Furthermore, detoxication was greater in the primary cell culture of liver cell obtained from the ET-treated rats after PB treatment than from those without PB treatment, because the production of acetylates (AAP) decreased and p-APG increased (induction of conjugated enzyme) in the PB treatment group.

Rapid determination of a new angiotensin-converting enzyme inhibitor, imidapril, and its active metabolite in human plasma by negative-ion desorption chemical ionization-tandem mass spectrometry (MS/MS)

A very rapid and highly sensitive method using desorption chemical ionization (DCI)-tandem mass spectrometry (MS/MS) with selected reaction monitoring is reported for the simultaneous determination of imidapril and its active metabolite (M1) in human plasma. Imidapril and M1 in plasma were extracted by a C18 solid phase extraction cartridge after deproteinization, and derivatized with pentafluorobenzyl bromide. One microliter of prepared sample was applied to the DCI filament and analyzed by DCI/MS/MS within a few minutes. The limits of determination of imidapril and M1 were 0.2 and 0.5 ng/ml in human plasma, respectively. The features of this method make it appropriate for use in pharmacokinetic studies with human plasma after oral administration of imidapril.

Determination of three metabolites of a new angiotensin-converting enzyme inhibitor, imidapril, in plasma and urine by gas chromatography-mass spectrometry using multiple ion detection

A specific and sensitive gas chromatographic-mass spectrometric method for the determination of three metabolites of the angiotensin-converting enzyme inhibitor, imidapril, in plasma and urine was developed. The metabolites were isolated from plasma and urine using a Bond Elut C18 solid-phase extraction cartridge. The isolated metabolites were converted to sensitive derivatives by pentafluorobenzyl bromide and heptafluoro-n-butyric acid anhydride. Following derivatization, the sample solutions were analysed by wide-bore column gas chromatography-mass spectrometry with multiple ion detection. The detection limits of the three metabolites were each 1 ng/ml in plasma and 5 ng/ml in urine. Analysis of the spiked plasma and urine samples demonstrated the good accuracy and precision of the method. This method was very useful for use in pharmacokinetic and bioavailability studies of the three metabolites of imidapril in humans.

Assay of nicergoline and three metabolites in human plasma and urine by high-performance liquid chromatography-atmospheric pressure ionization mass spectrometry

A method for the simultaneous determination of nicergoline and three of its metabolites in human plasma and urine has been developed using high-performance liquid chromatography-atmospheric pressure ionization mass spectrometry. Nicergoline and its metabolites were extracted from the plasma and urine samples with chloroform and separated on a reversed-phase ODS column. The eluents were led to the atmospheric pressure ionization interface and then analysed in the selected-ion monitoring mode. The detection limits of nicergoline and three of its metabolites were ca. 2 ng/ml in plasma and ca. 10 ng/ml in urine, at a signal-to-noise ratio of 4.

Metastatic vulvar Paget's disease responding to combination chemotherapy: case report

No effective chemotherapy for advanced extramammary Paget's disease has yet been established. A case of vulvar Paget's disease with systemic metastases was treated with a mitomycin C, vincristine and cisplatin combination chemotherapy, by which the vulvar lesion and serum CEA were clearly decreased. After surgery and 5-fluorouracil treatment, a similar combination chemotherapeutic regimen was administered to treat a recurrence, however, the lesions became resistant.

Malignant thymoma associated with liposarcoma of the mediastinum--a case report

Malignant thymoma occurring concurrently with mediastinal liposarcoma in a 49-year-old man is described. The patient underwent an incomplete resection of the mediastinal mass followed by irradiation therapy and additional chemotherapy. He died about 9 months after the detection of a mediastinal mass on chest X-ray films and the immediate cause of death was superior vena cava syndrome. The incidence of primary liposarcoma of the mediastinum alone is extremely rare. Only a few more than 20 with such a lesion have been documented in Japan. A review of the literature of patients with mediastinal liposarcoma and thymoma associated with malignancies revealed no case of an association of thymoma and liposarcoma.