[Detection of TDH-producing Vibrio parahaemolyticus O3:K6 from naturally contaminated shellfish using an immunomagnetic separation method and chromogenic agar medium]

We attempted to isolate TDH-producing Vibrio parahaemolyticus O3:K6 from shellfish. Asari samples were incubated with TSB supplemented with 2% (w/v) NaCl for 6 h, and then the 6-h cultures were incubated with salt polymyxin broth for 18 h. After the two-step enrichment, a 1 ml portion of the culture was treated with magnetic beads coated with K6 antibody for immunoconcentration of V. parahaemolyticus O3:K6. The immunoconcentrated and untreated cultures were plated onto a chromogenic agar and TCBS agar media for isolation of V. parahaemolyticus. TDH-producing V. parahaemolyticus O3:K6 was isolated from 3 out of 66 lots (4.5%) of naturally contaminated Asari. Six of 4,265 colonies suspected as V. parahaemolyticus (0.14%) were TDH-producing V. parahaemolyticus O3:K6.

Independence of timing and force control during finger-tapping sequences by pianists

To examine the relation between timing and forcc control during finger-tapping sequences by both the 10 pianists and the 13 nonpianists, participants tapped a force plate connected to strain gauges. A series of finger-tapping tasks consisted of 16 combinations of pace and peak force. Analysis showed that pianists had smaller correlation between intertap interval and peak force than nonpianists. Thus, force control was more independent of timing for pianists than for nonpianists.

Comparison of the relation between timing and force control during finger-tapping sequences by pianists and non pianists

To examine the relation between timing and force control during finger taping sequences by both pianists and nonpianists, participants tapped a force plate connected to strain gauges. A series of finger tapping tasks consisted of 16 combinations of pace (intertap interval: 180, 200, 400, or 800 ms) and peak force (50, 100, 200, or 400 g). Analysis showed that, although movement timing was independent of force control under low or medium pace conditions, there were strong interactions between the 2 parameters under high pace conditions. The results indicate that participants adapted the movement by switching from separately controlling these parameters in the slow and moderate movement to coupling them in the fast movement. While variations in the intertap interval affected force production by nonpianists, they had little effect for pianists. The ratios of time-to-peak force to press duration increased linearly in pianists but varied irregularly in nonpianists, as the required force decreased. Thus, pianists regulate peak force by timing control of peak force to press duration, suggesting that training affects the relationship between the 2 parameters.

Measurement of the midrapidity transverse energy distribution from square root of [(s)NN] = 130 GeV Au + Au collisions at RHIC

The first measurement of energy produced transverse to the beam direction at the Relativistic Heavy-Ion Collider at Brookhaven National Laboratory is presented. The midrapidity transverse energy density per participating nucleon rises steadily with the number of participants, closely paralleling the rise in charged-particle density, such that <E(T)>/<N(ch)> remains relatively constant as a function of centrality. The energy density calculated via Bjorken's prescription for the 2% most central Au+Au collisions at square root[s(NN)] = 130 GeV is at least epsilon(Bj) = 4.6 GeV/fm(3), which is a factor of 1.6 larger than found at sqrt[s(NN)] = 17.2 GeV ( Pb+Pb at CERN).

Clinical usefulness of the immunostaining of the tumor markers in pancreatic cancer

The effect of the rapid immunostaining of gastrointestinal cancer-associated antigens, CA19-9, CEA, DUPAN2, and CA50 was discussed for intraoperative pathological diagnosis of pancreatic cancer. The method can be completed in only 13 minutes with microwave irradiation to accelerate the incubation of the primary antibody. Only 3 seconds of irradiation at 500 W for fresh-frozen sections produced specific antigen staining of greater intensity than that obtained with longer incubation by the conventional method. Preservation of the tissue structure was satisfactory with minimal nonspecific background staining enabling us to diagnose the intrapancreatic spread of cancer. This method was also applied to intraoperative peritoneal washing cytology. As with frozen section biopsy, the sensitivity of intraoperative cytology is greater than by the conventional staining method, which is able to achieve more precise staging of pancreatic cancers. Our rapid immunoperoxidase staining method on the cryostat section of pancreatic biopsy specimens and on cytology samples provides important information to determine an appropriate operative approach for pancreatic cancer.

Binding rate constant of Tc-99m DTPA galactosyl human serum albumin measured by quantitative dynamic SPECT--clinical evaluation as a total and regional liver function test

To evaluate the clinical utility of a new method with dynamic single photon emission computed tomography (SPECT) and scatter and attenuation compensation to estimate both total and regional liver function quantitatively. Five controls, 20 patients with chronic liver disease, and 2 patients with Budd-Chiari syndrome were studied. Dynamic liver SPECT data were acquired during 20 minutes after injection of Technetium (Tc)-99m diethylenetriaminepentaacetic acid (DTPA) galactosyl human serum albumin (GSA) with scatter and attenuation compensation. The binding rate constant of Tc-99m GSA (Ku) was derived quantitatively from the Patlak plot based on kinetic models for GSA receptor binding. The mean Ku was obtained by dividing the Ku value (total Ku) by the liver volume. Both total and mean Ku were significantly lower in patients with chronic liver disease than in controls (302 +/- 112 vs. 523 +/- 78 ml/min; p < 0.001, 0.26 +/- 0.11 vs. 0.43 +/- 0.03 ml/min/cm3; p < 0.001). In the patient group, both total and mean Ku were significantly correlated with the results of conventional liver function tests and the histological severity of chronic liver disease. In 2 patients with Budd-Chiari syndrome, the mean Ku was lower in the right lobe, where the hepatic veins were occluded, than in the left lobe, where draining veins were patent. In conclusion, this method is a reliable diagnostic technique for estimating total and regional liver function.

Centrality dependence of charged particle multiplicity in Au-Au collisions at square root of (s)NN = 130 GeV

We present results for the charged-particle multiplicity distribution at midrapidity in Au-Au collisions at square root of [s(NN)] = 130 GeV measured with the PHENIX detector at RHIC. For the 5% most central collisions we find dN(ch)/d eta(vertical line eta = 0) = 622+/-1(stat)+/-41(syst). The results, analyzed as a function of centrality, show a steady rise of the particle density per participating nucleon with centrality.

Resistance to fulminant hepatitis and carcinogenesis conferred by overexpression of retinoblastoma protein in mouse liver

Previously, retinoblastoma (Rb) transgenic mice were produced under the control of the Rb gene promoter and showed dwarf characteristics. Here, we created transgenic mice, in which the human Rb gene was controlled by the hepatocyte nuclear factor-1 gene promoter/enhancer and was expressed primarily in the liver. The liver of these novel transgenic mice was normally developed. Intriguingly, these mice showed resistance to fulminant hepatitis induced by anti-Fas antibody as well as resistance to chemical carcinogenesis in the liver. These results show that the Rb protein acts as an anti-apoptotic and anti-oncogenic agent in vivo. Our novel construct may be useful as a gene cassette in gene therapy for prevention of fulminant hepatitis and hepatoma.

Glut1 expression in T1 and T2 stage colorectal carcinomas: its relationship to clinicopathological features

Glucose uptake is mediated by glucose transporter (Glut) proteins, which exhibit altered expression in a variety of malignant neoplasms. Glut1 expression is thought to be a potential marker for malignant transformation. The aim of the present study was to investigate the expression of Glut1 protein in colorectal adenomas, T1 and T2 stage carcinomas. Immunohistochemical detection of Glut1 protein was examined in 141 formalin-fixed and paraffin-embedded colorectal tumour specimens (57 adenomas, 84 carcinomas). The degree of Glut1 immunostaining of a specimen was graded according to the proportion of Glut1-positive cells in it; absent (positive cells are 0%), weakly positive (less than 10%), moderately positive (10-50%), and strongly positive (more than 50%). Glut1 expression was present in 18% of the adenomas with low-grade dysplasia, and in 63% of the adenomas with high-grade dysplasia. The positivity in such lesions was usually weak, but was moderate in 8% of the adenomas with high grade dysplasia. For the carcinomas, there were significant correlations between Glut1-positivity and depth of invasion (T1 45% versus T2 74%, P<0.01), histological differentiation (well 49% versus moderately to poorly 74%, P< 0.05) and morphological type (polypoid 42% versus depressed 73%, P< 0.05), if the cut-off value was set at 10% of cells. In conclusion, we clarified the relationship between Glut1 expression and clinicopathological features in T1 and T2 stage colorectal carcinomas, and our results suggested a high malignant potential of the depressed-type carcinoma.

Mechanism of action of aragusterol a (YTA0040), a potent anti-tumor marine steroid targeting the G(1) phase of the cell cycle

Aragusterol A (YTA0040), isolated from the Okinawan marine sponge of the genus Xestospongia, is a potent anti-tumor marine steroid that possesses a unique structural component. This compound showed broad-spectrum anti-proliferative activity against a panel of 14 human cancer cell lines (IC(50) = 0.01-1.6 microM). P-glycoprotein-mediated, multidrug-resistant cells showed cross-resistance to YTA0040 cells, whereas cisplatin-resistant non-small-cell lung-cancer (NSCLC) sublines showed a collateral sensitivity to YTA0040. In transplantable murine tumor models, YTA0040 displayed a broad spectrum and high degree of anti-tumor activity when administered i.p. or p.o. (life span T/C = 135-234%). In P388 murine leukemia cells, YTA0040 caused dose- and time-dependent suppression of nucleic acid and protein synthesis, with protein synthesis being more potently and rapidly inhibited than nucleic acid synthesis. Flow-cytometric analysis revealed that YTA0040 blocked the entry of human NSCLC-derived A549 cells into S phase, leading to arrest in the G(1) phase of the cell cycle. Western blot analysis demonstrated that YTA0040 caused a dose-dependent decrease in the levels of expression of hyperphosphorylated pRb and cyclin A in A549 cells. The level of p53 protein expression was decreased by YTA0040 treatment. A higher concentration of YTA0040 down-regulated the levels of expression of CDK2, CDK4, cyclin D1 and cyclin E. These findings indicated that YTA0040 arrested human NSCLC cells in late G(1) phase of the cell cycle through inhibition of pRb phosphorylation. Inhibition of pRb phosphorylation by YTA0040 resulted from down-regulation of levels of expression of the CDKs and cyclins involved in the G(1)/S transition and not from induction of p53 and/or the CDK inhibitor p21.

Detection of doxorubicin cardiotoxicity by using iodine-123 BMIPP early dynamic SPECT: quantitative evaluation of early abnormality of fatty acid metabolism with the Rutland method

BACKGROUND

To evaluate the possibility of predicting the development of doxorubicin-induced cardiomyopathy, we performed quantitative assessment of the early kinetics of iodine-123 beta-methyl-iodophenyl-pentadecanoic acid (I-123 BMIPP) by means of dynamic myocardial SPECT.

METHODS

Thirty-six patients with various malignancies were examined. I-123 BMIPP dynamic myocardial SPECT was performed before chemotherapy, after chemotherapy, or both. Immediately after the injection of I-123 BMIPP (111 MBq), 30-second dynamic SPECT data were acquired successively for 15 minutes. The left ventricular (LV) myocardium was divided into 8 segments in short-axial and vertical slices. By using the time-activity curve (TAC) of each myocardial segment [Mo(t)] as an output function and the TAC of the LV cavity [B(t)] as an input function, the Rutland equation, Mo(t)/B(t)= F + K Integral of(B(t)dt/B(t)), was used as a means of assessing all segments.

RESULTS

Mo(t)/B(t) showed a good linear correlation with Integral of(B(t)dt/B(t)) from 30 seconds to 4 minutes in all 456 segments. The mean K value of 8 LV segments was significantly lower after chemotherapy than before chemotherapy (0.071+/-0.019 [n = 21] vs. 0.095+/-0.025 [n = 36], P<.001). In 21 patients in whom dynamic SPECT was performed both before and after chemotherapy, the mean K values of left ventricle showed a significant decrease, from 0.101+/-0.024 to 0.071 +/-0.019 (P<.0001). The fractional change in the value of K after chemotherapy showed a significant linear correlation with the administered dose of doxorubicin (r = 0.648, P<.002).

CONCLUSION

I-123 BMIPP dynamic myocardial SPECT may be clinically useful, because it permits the early detection of doxorubicin-induced cardiomyopathy.

Flat-elevated and depressed, subtypes of flat early colorectal cancers, should be distinguished by their pathological features

Flat-type colorectal tumors have are being detected with increasing frequency. It has become clear that these flat lesions contain two subtypes; flat-elevated and depressed lesions. However, their clinicopathological features and roles in colorectal carcinogenesis remain obscure. We classified colorectal adenomas and submucosal invasive cancers into three types: polypoid, flat-elevated, and depressed types. A clinicopathological study of 2505 colorectal tumors (2407 adenomas, 98 submucosal invasive cancers) was then performed. Furthermore, 64 tumors (25 adenomas with high-grade dysplasia, 39 submucosal invasive cancers) from which DNA was extracted were examined for K-ras gene mutation. The percentages of each configuration in the resected materials were 62.0%, 36.4%, and 1.6% of the polypoid, flat-elevated, and depressed types, respectively. The rate of submucosal invasive cancer in the depressed type was always high regardless of size. In the polypoid and flat-elevated types, lesions of larger size showed higher rates of invasion. Analysis of submucosal invasive cancers revealed no adenomatous components in any of the depressed-type lesions; in the polypoid and flat-elevated types the frequencies of cancer with adenomatous components were 83.6% and 77.8%, respectively. The flat-elevated type was more frequently located (77.8%) in the proximal colon than the other types (polypoid type 16.4%, depressed type 25.0%). The incidence of K-ras gene mutation was 47.2%, 18.2%, and 0% in the polypoid, flat-elevated, and depressed types, respectively. These findings suggest that the flat-elevated and depressed types are similar in that they are both morphologically flat and have infrequent incidences of K-ras gene mutation, but these two lesions differ in their pathological features. Especially, depressed type lesions have a tendency to invade the submucosal layer even when they are small. Therefore one should always be aware of this type of lesion during colonoscopic examination.

[Right thoracotomy for reoperative mitral valve replacement]

We report a case of 67-year-old male who underwent reoperative mitral valve replacement through the right thoracotomy. He had undergone primary double valve replacement with mechanical valve for aortic valve and tissue valve for mitral valve respectively, and tricuspid annular plasty 11 years ago. The second operation was performed through the right thoracotomy under moderately hypothermic cardiopulmonary bypass. The mechanical valve was replaced via right side of left atrium approach under ventricular fibrilation at 25 centigrade of bladder temperature. He recovered well without any major complications.

Quantitative planar imaging method for measurement of renal activity by using a conjugate-emission image and transmission data

We are proposing a method to accurately measure renal activity in renography using Tc-99m labeled tracers. This method uses a conjugate-view image and transmission data for attenuation correction, the triple energy window (TEW) method for scatter correction, and background correction techniques that consider the source volume for accurate background activity correction. To examine this method in planar imaging, we performed two renal phantom studies with various uniform background activity concentrations. One study used two ideal box-shaped kidney phantoms with a thickness of 2 or 4 cm in a water tank and the other study employed two real kidney-shaped phantoms in a fillable abdominal cavity. For these studies the kidney phantom-to-background activity concentration ratio (S) was changed from 5 to infinity. The transmission data were obtained with an external Tc-99m line array source. The anterior- and posterior-view emission images were acquired with a dual-headed gamma camera simultaneously and the TEW method was used to correct scatter for the emission and transmission images. The results showed that this method with both the accurate background correction and scatter correction could give depth-independent count rates and could estimate the true count rate with errors of less than 5% for all S values. However, if either accurate background correction or scatter correction was performed alone, the absolute error increased to about 50% for the smaller S values. Our proposed method allows one to accurately and simply measure the renal radioactivity by planar imaging using the conjugate-emission image and transmission data.

Laparoscopic lower anterior resection is equivalent to laparotomy for lower rectal cancer at the distal line of resection

BACKGROUND

Procedures that involve resection of the distal rectum challenge the current limitations of laparoscopic technology, because of lack of compact articulating stapling instruments.

METHOD

We improve the procedure with the aid of a Lap disk, an abdominal wall sealing device that was developed for hand-assisted manipulation. A linear stapler capable of changing its stop angle is inserted through the disk, and the rectum is transected by the disk during a second pneumoperitoneum.

RESULTS

The transection line becomes equivalent to that obtained with laparotomy.

CONCLUSION

This new technique made laparoscopic lower anterior resection possible to transect the lower rectum in the same way as is done with laparotomy.

Studies on the mechanism of action of the gastric H+,K(+)-ATPase inhibitor SPI-447

3-Amino-5-methyl-2(2-methyl-3-thienyl)- imidazo[1,2-a]thieno[3,2-c]pyridine, SPI-447, is a potent gastric H+,K(+)-ATPase inhibitor, but a detailed mechanism of the inhibition is unknown. This study was designed to investigate the mechanism by which SPI-447 inhibits gastric H+,K(+)-ATPase. For this purpose, the inhibitory action of SPI-447 on gastric H+,K(+)-ATPase from porcine gastric mucosa was compared with that of omeprazole (an irreversible inhibitor) and SCH28080 (a reversible inhibitor). All compounds produced dose-dependent inhibition of gastric H+,K(+)-ATPase, and the inhibitory intensities were increased under acidic conditions. The anti-H+,K(+)-ATPase actions of SPI-447 and SCH28080 were attenuated by dilution, but not influenced by glutathione pretreatment. In contrast, that of omeprazole was not influenced by dilution, but was suppressed by glutathione pretreatment. KCl addition reversed the inhibition of H+,K(+)-ATPase-mediated H(+)-transport by SPI-447 and SCH28080, but had no effect on that by omeprazole. The anti-gastric H+,K(+)-ATPase action of SPI-447 was additive with that of SCH28080. SPI-447 and SCH28080 had no effect on Na+,K(+)-ATPase activity. These findings indicated that the inhibitory mechanism of SPI-447 on gastric H+,K(+)-ATPase was similar to that of SCH28080, but different from that of omeprazole; i.e., 1) reversible, 2) SH-group independent, 3) K(+)-competitive, and 4) highly specific against gastric H+,K(+)-ATPase.

[Practical compensation method of downscattered component due to high energy photon in 123I imaging]

We looked into the problem that the quantitative values of 123I data vary according to collimator type. First, we made the assumption that the quantitative values of 123I data are degraded by the scattered photons from the 529 keV component which contaminate the 159 keV imaging data. Then, the 123I Dual Window (IDW) method was proposed to improve the quantitative values of the 123I data. The IDW method uses the energy window on the high-energy side to estimate the amount of scattered 529 keV photons which contaminate the 159 keV data. Since only a dual-energy window acquisition and a simple image processing are needed, the IDW method can be performed in most conventional gamma camera systems. In the torso phantom studies, the IDW method reduced the error in the semi-quantitative value 'heart/mediastinum (H/M) ratio' in 123I-MIBG myocardial scintigraphy from 22% to 1%. The results of the phantom studies indicate that the IDW method can improve the quantitative values of 123I data.

Reduced expression of the CDK inhibitor p27(KIP1) in rat two-stage bladder carcinogenesis and its association with expression profiles of p21(WAF1/Cip1) and p53

The cyclin-dependent kinase (CDK) inhibitor p27(KIP1) exerts its growth suppressive effects by targeting the cyclin-CDK complexes. Reduced protein levels of p27(KIP1) have been reported in numerous human cancers and this has been attributed to increased degradation. However, few reports have addressed the significance of p27(KIP1) expression in chemical carcinogenesis of rodents. In a rat two-stage urinary bladder carcinogenesis model, with N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) initiation followed by promotion with sodium L-ascorbate (Na-AsA), we evaluated the expression of p27(KIP1) protein using immunohistochemistry during various stages of urinary bladder carcinogenesis. In addition, we evaluated the mRNA expression profiles for p27(KIP1), p21(WAF1/Cip1) and p53 in tumors. Fisher 344 rats were initiated with 0.05% BBN in the drinking water for 4 weeks and then administered 5% Na-AsA in the diet. Immunohistochemical examination revealed p27(KIP1) protein to be constitutively expressed in normal urothelium, simple hyperplasia and in most papillary and nodular (PN) hyperplasias and small papillomas, but diminished or absent in large papillomas and in transitional cell carcinomas. An inverse correlation between expression of p27(KIP1) and cell proliferation was generally observed. Quantitation of mRNA by multiplex reverse transcription-PCR showed a significant downregulaton of p27(KIP1), p21(WAF1/Cip1) and p53 mRNA in tumors. More than 50% reduction in p27(KIP1) mRNA expression was observed in 42 and 47% of tumors at weeks 18 and 24, respectively; similar reduction in p21(WAF1/Cip1) mRNA expression was observed in 58 and 73% of tumors at weeks 18 and 24, and in p53 mRNA expression in 50 and 73% of tumors at weeks 18 and 24, respectively. None of the 25 tumors we examined by PCR-single-strand conformational polymorphism analysis had p53 mutations. These data imply that abnormal down-regulation of p27(KIP1), p21(WAF1/Cip1) and/or p53 in tumor cells may contribute to the malignant progression of tumors during rat two-stage bladder carcinogenesis.

[The analysis for surgical procedures of coronary-artery bypass grafting: selection of graft materials]

We analyzed 222 patients undergoing coronary artery bypass grafting (CABG) in our institute. Our selection of graft materials consists of only one arterial conduit and one or more saphenous vein grafts (SVG). An arterial conduits (left internal thoracic artery (LITA) was mainly used for the left anterior descending coronary artery (LAD), while a SVG was used for coronary arterial branch. Our approach was evaluated by the mid-term prognosis as well as cardiac events. Seventy-one percent of patients with CABG could be followed. The graft patency rate was better for ITA grafts than for SVG (97.8% vs 88%). The incidence of late cardiac events was lower in patients with the LITA, to the LAD. Furthermore, these patients had a better survival rate at 4 years comparing with patients who had vein bypass grafts alone. We suggest that this selection of graft materials may be accepted in CABG for the good quality, avoiding the cardiac events.

Microsatellite analysis of childhood leukemia: correlation of 9p and 12p chromosome abnormalities with expression of related genes

BACKGROUND

Loss of heterozygosity (LOH) and DNA replication error (RER) have been thought to be involved in carcinogenesis, but have not been investigated in childhood leukemia and lymphoma.

METHODS

Eighty samples from 65 patients with childhood leukemia and lymphoma were examined using seven different microsatellite markers for RER analysis. Additionally, LOH in two chromosome regions (9p and 12p) was investigated. Furthermore, expression of the TEL, TEL/AML1 and p27(KIP1) genes on 12p and the p16 gene on 9p were detected by reverse transcriptase polymerase chain reaction.

RESULTS

Replication errors were detected in 5/65 patients (7.7%). Most (4/5 patients) RER were preferentially located in the 9p and 12p regions. There were two patients who had DNA abnormalities in both 9p and 12p, one with common acute lymphoblastic leukemia (ALL) showed 9p LOH and the TEL/AML1 fusion gene on 12p and the other with common ALL and 12p RER had diminished expression of both the p27(KIP1) gene on 12p and the p16 gene on 9p.

CONCLUSIONS

Combined DNA alterations on 9p and 12p, involving LOH, RER and/or gene mutation and chromosomal translocation, were found in childhood acute leukemia, especially in common ALL.

Inhibition of liver glutathione S-transferase placental form-positive foci development in the rat hepatocarcinogenesis by Porphyra tenera (Asakusa-nori)

The effects of Asakusa-nori, Porphyra tenera (PT), a popular edible seaweed in Japan, on the development of putative preneoplastic lesions, glutathione S-transferase placental form (GST-P)-positive foci, in the male F344 rat liver were examined using a medium-term bioassay system. PT significantly decreased both the number and area of GST-P-positive foci in rat livers initiated with diethylnitrosamine (DEN). To investigate possible mechanisms of inhibition, effects of PT on 5-bromo-2'-deoxyuridine (BrdU) labeling in GST-P-positive foci and the surrounding area of hepatocytes were studied. The ratio of the GST-P-positive foci to surrounding tissue labeling indices was decreased in the PT-treated group as compared with the DEN alone group. Ornithine decarboxylase activity in the liver was slightly increased and spermidine/spermine N'-acetyltransferase activity was slightly decreased in the PT-treated animals. These results suggest that PT possesses chemopreventive effects against DEN-induced hepatocarcinogenesis.

Feasibility of simultaneous stress 99mTc-sestamibi/rest 201Tl dual-isotope myocardial perfusion SPECT in the detection of coronary artery disease

This study assesses feasibility and diagnostic accuracy of simultaneous stress 99mTc-sestamibi/rest 201 TI dual-isotope myocardial perfusion SPECT with Moore's correction method, in which contamination originating from lead x-rays produced in a collimator was subtracted in the 201TI windows.

METHODS

Eighty-one patients with suspected coronary artery disease received exercise 99mTc-sestamibi injection, followed by rest 201TI injection 50 min later, and dual-isotope SPECT was performed (group 1). These results were compared with coronary angiographic findings. Furthermore, to estimate the accuracy of Moore's correction method, 201TI crosstalk into the 99mTc acquisition window (group 2A, n = 20) and 99mTc crosstalk into the 201TI acquisition windows (group 2B, n = 20) were studied. For group 2A, stress 99mTc-sestamibi SPECT (single 99mTc-sestamibi SPECT) was performed, followed by 201TI injection at rest and dual-isotope SPECT acquisition 50 min later. For group 2B, rest 201TI SPECT (single 201TI SPECT) was performed, followed by 99mTc-sestamibi injection at rest and dual-isotope SPECT acquisition 30 min later.

RESULTS

Sensitivity and specificity in group 1 were 83% and 99%, respectively, when > or =75% coronary artery narrowing was considered significant. In groups 2A and 2B, SPECT images were divided into 24 segments, and relative regional uptake in each segment was obtained. In group 2A, relative regional uptake of single 99mTc-sestamibi SPECT correlated well with that of dual-isotope SPECT (r = 0.942). In group 2B, relative regional uptake of single 201TI SPECT correlated well with that of dual-isotope SPECT (r = 0.935). Furthermore, in low 201TI uptake segments with relative regional uptake in both single- and dual-isotope SPECT of < or =70%, the degree of concordance between single- and dual-rest 201TI was considered to be high with Bland-Altman analysis and the kappa statistic. Comparison of perfusion defect type demonstrated that, of 22 stress defects within infarct zones, 95% were irreversible and 5% were reversible. In contrast, of 28 stress defects within stenosed vessel zones in noninfarct zones, 89% were reversible and 11% were irreversible (P < 0.0001 versus infarct zones).

CONCLUSION

Simultaneous dual-isotope imaging with Moore's correction method is feasible, with acceptable accuracy for detection of coronary artery disease and a small amount of crosstalk into each window.

Effects of scatter and attenuation correction on quantitative analysis of beta-CIT brain SPET

The aim of this study was to evaluate the effects of scatter correction (SC) and attenuation correction (AC) on the quantification of dopamine transporters using 123I-beta-CIT brain SPET images. Quantitative analysis was carried out using static SPET images obtained 23 h after injection. We calculated V3" [(striatal-occipital)/occipital ratio] values from images without correction, with AC, and with SC and AC. Two types of regions of interest (ROI) were placed on the striatum: a small square ROI and a larger ROI containing most of the striatum. After validating the correction method in a phantom experiment, a human study was carried out involving eight normal volunteers and 15 patients. The larger ROI yielded smaller V3" values. The effect of attenuation correction was modest, whereas that of scatter correction was marked. It was shown that beta-CIT SPET quantification was affected by the size of the ROI, photon scattering and attenuation, and that scatter and attenuation correction improved the accuracy of the quantification. Methodological standardization in image processing and the type of ROI should be considered when a multi-centre trial is planned.

Successful use of high frequency oscillatory ventilation for pneumomediastinum

An infant with pneumomediastinum due to mechanical ventilation was successfully treated using high frequency oscillatory ventilation (HFOV). The 3-month-old male had undergone ligation of a patent ductus arteriosus and suffered from barotraumatic pneumomediastinum in the postoperative period. Computed tomography of the chest confirmed the diagnosis. While using conventional mechanical ventilation the respiratory failure worsened. HFOV was instituted and the patient improved. A lower airway pressure by this mode of ventilation provided significant advantages in the patient with an air leak. He was subsequently extubated and discharged home.