P6453Activation of necroptotic pathway by downregulated caspase-8 expression is associated with progression of left ventricular remodeling in nonischemic dilated cardiomyopathy

Background

Necroptosis, a form of programmed necrosis, has been suggested to be involved in the pathogenesis of various pathological conditions including heart failure. Protein expression of caspase-8, an endogenous inhibitor of necroptosis, is reported to be downregulated in human failing hearts, but its clinical significance remains unclear.

Methods

Endomyocardial biopsy specimens were obtained from patients with nonischemic dilated cardiomyopathy (n=57, 56.2±14.5 years old, 70% male). The area stained with antibodies against caspase-8 and phospho-MLKL-Ser358 was calculated using an image analyzer, and fibrotic and cardiomyocyte areas were determined by Masson's Trichrome staining. Using a level of median caspase-8 expression (6.04% of the area of the myocardium with caspase-8 signal), patients were classified into a high caspase-8 expression group (H-cas8) and a low caspase-8 expression group (L-cas8).

Results

Caspase-8 signals were detected in cytoplasm and intercalated disks of cardiomyocytes. Patients in the L-cas8 group was younger (51.3±13.1 vs. 61.2±14.3 years old) and had larger left ventricular end-diastolic volume (LVEDV: 174±49 vs. 131±41 ml), larger left ventricular end-systolic volume (LVESV: 123±51 vs. 87±39 ml), and higher ratio of mitral peak velocity of early filling to late diastolic filling (E/A: 1.94±1.48 vs. 1.12±0.66) compared with the H-cas8 group. Caspase-8 expression level was positively correlated with age (r=0.34, p=0.01) and negatively correlated with LVEDV (r=−0.47, p<0.01), LVESV (r=−0.40, p<0.01), and E/A (r=−0.39, p<0.01) in simple linear regression analysis. The extent of myocardial fibrosis was not correlated with caspase-8 expression level. Multiple regression analysis indicated that LVEDV, LVESV, and E/A were independent explanatory factors of caspase-8 expression level after adjusting age and sex. Phospho-MLKL signals, an index of activation of necroptotic pathway, were frequently observed in cytoplasm, intercalated disks, and nuclei in the L-cas8 group but not in the H-cas8 group.

Conclusion

Lower caspase-8 expression in cardiomyocytes was associated with increased phosphorylation of MLKL and larger left ventricular volume, suggesting that downregulated caspase-8 may contribute to progression of myocardial remodeling via activation of MLKL in human dilated cardiomyopathy.

Ambipolar organic field-effect transistors based on solution-processed single crystal microwires of a quinoidal oligothiophene derivative

A simple and versatile solution-processing method based on molecular self-assembly is used to fabricate organic single crystal microwires of a low bandgap quinoidal oligothiophene derivative. Individual single crystal microwire transistors present well-balanced ambipolar behaviour with hole and electron mobilities as high as 0.4 and 0.5 cm(2) V(-1) s(-1), respectively.

Influence of the grain orientation on the charge transport properties of organic field-effect transistors

We report the effects of crystalline grain orientation on the charge transport properties of a J-aggregate bisazomethine dye (DE2) in thin films.

[Development of a simple method for the washout correction of 123I-IMP SPECT and its application to a quantitative rCBF method]

We have developed a simple method to correct the washout of tracer from the brain based on the two-compartment model in brain early SPECT using N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). This correction was applied to a new quantitative method of regional cerebral blood flow (rCBF) in combination with the microsphere method by continuous arterial sampling previously reported. Data acquisition of 123I-IMP early SPECT was started from 35 min after 123I-IMP i.v. injection, and the time activity curve of whole brain on anterior head planar images was monitored immediately after 123I-IMP i.v. injection for the correction of washout of tracer from the brain. The usefulness of this method was evaluated in 12 patients with various brain diseases by comparison with the results obtained from the super-early SPECT at 7-10 min after 123I-IMP i.v. injection. The washout rates in cases of early SPECT corrected by this method ranged from 16.91% to 39.34% with a mean +/- SD of 27.72 +/- 5.44%. The contrast of hypo- to hyperperfusion regions on early SPECT was improved by the correction of the washout, and its intracerebral distribution was similar to the simultaneously obtained super-early SPECT images. These results indicated that the present correction method for the washout was useful for more correct quantification of rCBF.

[Compartment analysis of 123I-iomazenil brain on early and delayed SPECT]

We investigated the characteristics of 123I-Iomazenil (IMZ) SPECT images in 12 adults (six males and six females, with a mean age of 56.1 years). The washout rate of 123I-IMZ from the brain was estimated from two SPECTs done 15 min and 3 hr after injection. Although the washout was relatively slow, the rates differed in each intracerebral region, suggesting that the distribution of 123I-IMZ was gradually changing. Furthermore, assuming 123I-IMZ kinetics in the brain for the three-compartment, two-parameter model, the transition rate constant (K1) from the blood to the brain and the binding potentials (BP) of benzodiazepine to the receptor were calculated. The BP and K1 values were compared with 123I-IMZ SPECT counts and CBF values by 123I-IMP. The BP values correlated more closely with the counts on the delayed SPECT than those on the early SPECT. It was confirmed that delayed SPECT images reflect better the distribution of the benzodiazepine receptor than early images do. On the other hand, the K1 values correlated highly with CBF obtained by 123I-IMP, and this finding suggested that super-early SPECT images might be remarkably influenced by the distribution of CBF.

A survey of ciguatera: assessment of Puako, Hawaii, associated with ciguatera toxin epidemics in humans

A survey for the assessment of the ciguatera problem has been determined in Puako, South Kohala, on the Island of Hawaii. This is in the area of persistent ciguateric outbreaks during the months of January through March, caused by a specific species of fish (Cheilinus rhodochrous, red rose wrasse, or po'ou). Analyses of algae, Gambierdiscus toxicus, and various species of fish, including herbivores and carnivores, gave positive indications of Puako as a potential ciguateric area. Algae associated with Gambierdiscus toxicus blooms and the dinoflagellate itself were found in transects A and D. Transects A and D showed 291 G. toxicus per gram of Tolycarpidia glomurata and 9 G. toxicus per gram of Turbinaria sp. with epiphytic Jania sp., respectively. No G. toxicus was found in transects B and C. This may be attributed to the low salinity from intrusion of freshwater in this vicinity. Examinations of the fish, kole, manini, Hawaiian kole, roi, and po'ou by the solid-phase immunoassay showed 89% of fish in the borderline and positive categories from all transects. Extracts of viscera and flesh showed high levels of toxicity in mouse (13 of 23 deaths), particularly in the viscera (gut) of both herbivores and carnivores. The guinea pig atrial analysis generally showed a few ciguatoxin-like, but most were nonciguateric type responses. The data presented in this Puako survey showed evidence of toxic fish associated with ciguatoxin-like and most probably other toxins, either polyethers or non-polyethers as yet unidentified.

[Usefulness of 99mTc-ECD SPECT in diseases of the central nerve system: special reference to a comparison with 123I-IMP and 99mTc-HM-PAO SPECT]

The usefulness of a new cerebral perfusion imaging radiopharmaceutical, 99mTc-ethyl cysteinate dimer (ECD), was clinically evaluated. The subjects of this study were 14 patients with neurological disorders including 10 patients with cerebral infarction and 4 patients with other diseases. A total of 15 examinations was performed. 99mTc-HM-PAO or 123I-IMP SPECTs were performed simultaneously, and the findings from those examinations were compared with 99mTc-ECD. As to the count ratio of lesions to normal area (L/N), the L/N ratio in severe ischemic patients was lower in 99mTc-ECD than in 99mTc-HM-PAO or 123I-IMP. In mild ischemic patients, on the other hand, the L/N ratio was the lowest in 123I-IMP. When the relationship between rCBFs obtained from 123I-IMP and the values of L/N in 99mTc-ECD or 99mTc-HM-PAO was compared, the values of L/N in 99mTc-ECD or 99mTc-HM-PAO were found to have decreased linearity with increasing rCBF. In a patient showing luxury perfusion, the accumulation pattern of 99mTc-ECD was different from that of the other two radiopharmaceuticals, and focal defect was revealed in 99mTc-ECD SPECT. On the dynamic SPECT of 99mTc-ECD in a patient with meningioma, the tumor showed a change from high to low perfusion with the passage of time. This finding indicated that care should be taken in the evaluation of accumulation of 99mTc-ECD. Therefore, 99mTc-ECD was found to be useful as a cerebral perfusion agent. In addition, as accumulation of 99mTc-ECD might somehow reflect metabolism in some cases, further careful investigation of many cases should be carried out.

[A fundamental study of 99mTc-ethyl cysteinate dimer (99mTc-ECD)]

In vitro fundamental studies of 99mTc-ethyl cysteinate dimer (99mTc-ECD), a newly developed radiopharmaceutical for cerebral perfusion scintigraphy, were performed, and were compared with those of 99mTc-HM-PAO, which has been widely applied to clinical use. 99mTc-HM-PAO should not only be injected soon after reconstitution, but also be avoided mixture with saline or drugs such as Diamox, because of its radiochemical purity decreases with the passage of time and the addition of saline and Diamox. On the other hand, the radiochemical purity of 99mTc-ECD reached a constant level of 94-96% at 30 to 180 min after reconstitution, and it remained stable against the addition of saline and Diamox. Therefore, it was suggested that 99mTc-ECD could be injected from an already saline-infused venous-line or mixed with Diamox. However, early injection after reconstitution should be avoided, because 99mTc-ECD did not become stable enough to maintain sufficient radiochemical purity until 30 min after reconstitution. The present studies are suggested that the red blood cell component is largely related to the metabolism of 99mTc-ECD in blood. Furthermore, from study of the metabolic rate using rabbit blood, it was suggested that a species difference existed in esterase activity in blood.

[Single photon emission computed tomography by using N-isopropyl-p-[123I]-iodoamphetamine and 99mTc-hexamethyl propyleneamine oxime in a patient with herpes simplex encephalitis]

Single photon emission computed tomographies (SPECTs) by using N-isopropyl-p-[123I-IMP]-iodo-amphetamine (123I-IMP) and 99mTc-hexamethyl propyleneamine oxime (99mTc-HM-PAO) were serially performed in a 70 yrs. old male with herpes simplex encephalitis (HSE), and the chronological changes of accumulations were studied. Accumulations of both 123I-IMP and 99mTc-HM-PAO increased initially, and then decreased with the stage of HSE being advanced. The sequential appearance of the lesion in HSE with 123I-IMP and 99mTc-HM-PAO SPECTs was as same as that reported previously by X-CT; beginning at the temporal lobe with eventually being spread to the occipital and frontal lobe. Furthermore, it was shown that findings of both SPECTs could reflect considerably the clinical features, and the laboratory data in central spinal fluid. Thus, 123I-IMP and 99mTc-HM-PAO SPECTs seemed to be a useful tool in the diagnosis, deciding of whether the treatment was suspended or continued, and clarifying the pathophysiology in HSE.

[A case of Creutzfeldt-Jakob disease followed up by N-isopropyl-[123I]-p-iodoamphetamine and 99mTc-hexamethylpropyleneamine oxime SPECT]

N-isopropyl-[123I]-p-iodoamphetamine (123I-IMP) and 99mTc-hexamethylpropyleneamine oxime (99mTc-HM-PAO) SPECT were performed in a 66 yrs-old female patient with Creutzfeldt-Jakob disease (CJD). The decreased accumulation of both radiopharmaceuticals, which localized initially in the focal regions and progressed eventually to the whole brain, were observed in the early stage of CJD, when no abnormal findings were obtained on X-CT. Although the redistribution of 123I-IMP was recognized in the relatively early stage in which the accumulation was significantly decreased, it disappeared with the progression of the disease. The accumulation of both radiopharmaceuticals which decreased remarkably in the early stage of CJD was sustained in low level during the chronic stage. The accumulation ratio of 99mTc-HM-PAO, after second examinations, to that on first SPECT was lower than those of 123I-IMP. It was suggested, as this cause, that the difference of the accumulation mechanism of both agents might be concerned. Thus, it is interested to follow up a patient with CJD by using 123I-IMP and 99mTc-HM-PAO SPECT, and this modality will provide a useful information to clarify the pathogenesis of CJD.

[Clinical usefulness of a dual photon absorptiometry system using X-ray for peripheral bone--comparison with a single photon absorptiometric system]

A newly developed dual photon absorptiometry system (DCS-600, ALOKA Co., LTD.) using two monochromatic X-rays for the determination of bone mineral in the peripheral bone was fundamentally studied, in comparison to single photon absorptiometry system (SPA). The accuracy and precision in DCS-600 were equal to or better than SPA system. Furthermore, in DCS-600 the forearm could be imaged, and the manipulation was easy. Thus DCS-600 was found to be a good instrument as a quantifying system of bone mass.

Visualization of ocular melanoma with N-isopropyl-p-[123I]-iodoamphetamine

In a patient with ocular melanoma, scintigraphy with N-isopropyl-p-[123I]-iodoamphetamine [( 123I]IMP) clearly delineated the histologically proven ocular lesion. In a tissue distribution study, using the resected specimen, a significantly high accumulation of the radioactivity was confirmed in tumor tissue. Thus, [123I]IMP scintigraphy provided specific localization of an ocular melanoma.

Usefulness of bone imaging in diagnosis of sternocostoclavicular hyperostosis

Four patients with sternocostoclavicular hyperostosis showing characteristic abnormal uptake on bone imaging are described. Bone imaging was useful in the diagnosis of sternocostoclavicular hyperostosis.

[Clinical study on the measurement of squamous cell carcinoma (SCC)--related antigen in SCC]

By using a RIA Kit for squamous cell carcinoma (SCC) antigen, extracted and purified this substance from liver metastasis of SCC of the uterine cervix, a fundamental and clinical study has been done. Based on the fundamental study, it was shown that this kit was useful clinically. High concentrations of serum SCC related antigen were observed in squamous cell carcinoma of the lung, head and neck, and uterus. It was recognized that the measurement of serum SCC related antigen was useful in not only diagnosis, but also in the evaluation of effectiveness of therapy or prediction of recurrence. In particular, as there is a lack of reliable tumor markers in head and neck tumors, good results can be anticipated from the measurement of SCC related antigen in such cases.

The usefulness of bone-marrow scintigraphy in the detection of bone metastasis from prostatic cancer

We used a combination of bone and bone-marrow scintigraphy to study 25 patients with prostatic cancer. Of the 18 cases whose 99mTc-methylene diphosphonate (MDP) bone scans showed hot spots in the lower lumbar region of the spine and/or the pelvic bone, 8 had normal bone-marrow scintigrams. These 8 patients were subsequently shown to have senile, degenerative changes of the spine. On the other hand, in 9 of the 10 patients whose bone-marrow scintigrams showed accumulation defects, follow-up study and characteristic X-ray findings confirmed the presence of metastases. In all 6 cases with extensive bone metastases shown by 99mTc-MDP bone scintigraphy, 99mTc-sulphur-colloid bone-marrow scintigraphy showed multiple accumulation defects. In conclusion, bone-marrow scintigraphy was found to be useful in distinguishing metastatic lesions from benign degenerative changes in the cases with suspected bone involvement, as well as in evaluating equivocal lesions in the pelvis.

[Clinical study of the measurement of tissue polypeptide antigen in patients with breast cancer]

Tissue polypeptide antigen (TPA) concentrations in patients with breast cancer were measured using a radioimmunoassay (RIA) kit. Although this RIA kit presented some problems in the dilution test of high-concentration samples, it was found to be adequate for clinical use. It was shown that the measurement of serum TPA concentration was useful in monitoring the local recurrence, for the early diagnosis of distant metastasis and for evaluating the therapeutical effect after surgery. TPA concentration showed no correlation with CEA concentration. Therefore, in order to raise the rate of diagnostic success, simultaneous measurement of both TPA and CEA was essential.

Metastatic medullary thyroid cancer: localization with iodine-131 metaiodobenzylguanidine

A patient in whom metastatic medullary thyroid cancer was diagnosed underwent a scintigraphic examination using [131I]MIBG. Multiple hot lesions and diffuse hepatic uptake were noted corresponding to bone and liver metastases. Iodine-131 MIBG may prove to be useful for scintigraphic localization and for the treatment of medullary thyroid cancer as in pheochromocytoma and neuroblastoma.

Usefulness of liver scan using 99mTc-phytate in diagnosis of partial diaphragmatic eventration

Partial diaphragmatic eventration, when occurring at uncommon sites, is difficult to diagnose when only using a plain X-p and fluoroscopy. We experienced an unusual variety of this disorder. In order to diagnose this case, liver scintigraphy using 99mTc-phytate was performed, and we were able to make a definite diagnosis without other invasive examinations.

Role of FeCl3 in 67Ga uptake by HeLa S3 cells in vitro

The effect of FeCl3 on 67Ga uptake by HeLa S3 cells was studied in vitro. Uptake of 67Ga by HeLa S3 cells was influenced by the concentrations of serum in the medium and especially that of transferrin added to the medium. Therefore, it is assumed that a mechanism of 67Ga uptake exists mediated by transferrin. However, when 10(-2)--10(-1) mM FeCl3 was added to the medium in the same experimental system, a remarkable increase of 67Ga uptake was noted. Results of equilibrium dialysis, showed that binding of 67Ga to transferrin was inhibited by the administration of FeCl3. Moreover, the formation of a complex of 67Ga and FeCl3, which did not pass through the cellulose membrane, was observed. A correlation was found between an increase in 67Ga uptake by HeLa S3 cells and the formation of the 67Ga--Fe complex. These results indicate that another mechanism of 67Ga accumulation, namely the formation of a 67Ga--Fe complex plays a role in the uptake of 67Ga by tumor cells in the presence of iron.