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Fast fluid-attenuated inversion recovery (FAST-FLAIR) of ischemic lesions in the brain: comparison with T2-weighted turbo SE.

PURPOSE: We compared fast fluid-attenuated inversion recovery (FAST-FLAIR) images with Turbo SE T2-weighted images to evaluate the detectability of small ischemic lesions in the brain. MATERIALS AND METHODS: Thirty-six cases of multiple cerebral ischemic lesions were examined with FAST-FLAIR and Turbo SE imaging. The detectability of lesions, ability to discriminate lesions from the cortex, visualization of perivascular space, and visualization of brainstem lesions were compared between the two sequences. RESULTS: The total number of lesions detected on both sequences was 534 in 36 cases. Six lesions in three cases were detected only on FAST-FLAIR, and one lesion in one case was detected only on the Turbo SE. All the 52 lesions located close to the cortex could be discriminated from the cortex on the FAST-FLAIR images, while 23 of these lesions could not be discriminated on the Turbo SE. Perivascular spaces were not visualized as areas of high signal on the FAST-FLAIR images. Pontine lesions that were visualized in four cases were clearer on the Turbo SE images than on the FAST-FLAIR images. CONCLUSION: The FAST-FLAIR images were shown to be useful in the detection of ischemic lesions and in distinguishing them from the surrounding normal structures. The FAST-FLAIR sequence is expected to become a new additional routine sequence.

Aged↗

Fluorine-18-fluorodeoxyglucose and carbon-11-methionine evaluation of lymphadenopathy in sarcoidosis.

UNLABELLED: Uptake of 18F-fluorodeoxyglucose (FDG) and 11C-methionine (Met) in mediastinum and hilar lymph nodes was studied using PET in 31 patients with sarcoidosis. The aim of our study was to examine whether these different tracers play a differential role in clinical assessment of pulmonary involvement. METHODS: Fluorine-18-fluorodeoxyglucose and 11C-Met PET were administered on different days. The differential absorption ratio of these tracers was calculated for the region of interest with the highest level of activity. Clinical reassessment of sarcoidosis was made at least 1 yr after the first PET examination. In seven patients whose lymph nodes still remained visible by other imagings at the time of reevaluation, the same PET study was performed again. RESULTS: Both FDG and Met were accumulated in the lymph nodes in all but one patient. The FDG and Met uptake ratios in all patients were not correlated, but they could be divided into the FDG-dominant group (FDG/Met uptake ratio > or = 2) and the Met-dominant group (FDG/Met uptake ratio < 2). Within each group, the FDG and Met uptake values were correlated. The rate of improvement assessed by clinical status and chest radiographs was considerably higher in the FDG- (78%) than in the Met-dominant group (33%). In the seven patients of the repeated PET examination, their FDG/Met uptake ratios were generally unchanged after 1 yr. CONCLUSION: The results suggest that the FDG/Met uptake ratio using PET may reflect the differential granulomatous status in sarcoidosis and be a useful tool for pretreatment evaluation.

Adult↗

Optimization of Butterworth filter for brain SPECT imaging.

A method has been described to optimize the cutoff frequency of the Butterworth filter for brain SPECT imaging. Since a computer simulation study has demonstrated that separation between an object signal and the random noise in projection images in a spatial-frequency domain is influenced by the total number of counts, the cutoff frequency of the Butterworth filter should be optimized for individual subjects according to total counts in a study. To reveal the relationship between the optimal cutoff frequencies and total counts in brain SPECT study, we used a normal volunteer and 99mTc hexamethyl-propyleneamine oxime (HMPAO) to obtain projection sets with different total counts. High quality images were created from a projection set with an acquisition time of 300-seconds per projection. The filter was optimized by calculating mean square errors from high quality images visually inspecting filtered reconstructed images. Dependence between total counts and optimal cutoff frequencies was clearly demonstrated in a nonogram. Using this nomogram, the optimal cutoff frequency for each study can be estimated from total counts, maximizing visual image quality. The results suggest that the cutoff frequency of Butterworth filter should be determined by referring to total counts in each study.

Brain↗

Management of malignant tracheobronchial stenosis with metal stents and Dumon stents.

BACKGROUND: Tracheobronchial stenosis caused by malignancy is a life- threatening problem. Stenting is one of the treatment modalities and recently has been used widely for the management of such stenosis, but we do not have a clear guide as to which stent should be selected. METHODS: We evaluated 25 patients (19 men, 6 women; mean age, 60.7 years; range, 34 to 77 years) received 24 metal stents (four covered with silicone rubber) and three Dumon stents. All 25 patients had severe dyspnea because of airway stenosis caused by malignant tumors. RESULTS: Among the 25 patients, airway obstruction due to extrinsic compression by tumor developed in 11 and was treated with a bare metal stent. The airway remained patent in 10 patients. In 16 patients with intraluminal tumor invasion, nine lesions were treated with a bare metal stent, four lesions with a covered metal stent, and the remaining three lesions with a Dumon stent. Recurrent stenosis did not occur in any patient with a covered metal stent or a Dumon stent. However, restenosis occurred in 4 patients with a bare metal stent, all of whom received laser therapy. In all patients, stenting immediately relieved dyspnea. Six patients lived for 32 days to 53 months after stenting, and 19 patients died of primary malignancies with a mean survival of 131.9 days. CONCLUSIONS: Metal stents are effective in treating malignant extrinsic tracheobronchial compression. The use of covered metal stents or Dumon stents is preferable for intraluminal stenosis due to malignant growth.

Adult↗

Pathologic characteristics and surgical indications of superacute type A intramural hematoma.

BACKGROUND: The treatment policy for acute intramural hematoma involving the ascending aorta remains controversial. METHODS: This study compared the pathologic characteristics of intramural hematoma with those of acute aortic dissection with a false lumen. The study group comprised 69 patients with intramural hematoma and 156 with acute aortic dissection who underwent emergency operation between 1995 and 2003. RESULTS: Patients were significantly older in the intramural hematoma group than in the dissection group (67.7 +/- 7.2 years compared with 59.8 +/- 11.6 years; p < 0.0001). Pericardial hemorrhage was present in a higher proportion of patients in the intramural hematoma group than in the dissection group (66.7% compared with 50.6%; p = 0.0257). Three patients (4.3%) died in the intramural hematoma group, whereas 26 patients (16.7%) died in the dissection group (p = 0.011). Histopathologic examination showed no difference in the severity of medial changes, but the site of dissection differed. The thickness of the residual media of the adventitia side was 0.21 +/- 0.12 mm in the intramural hematoma group compared with 0.32 +/- 0.22 mm in the acute aortic dissection group. Dissection was significantly nearer the adventitia in the intramural hematoma group (p = 0.0016). CONCLUSIONS: Dissection is nearer the adventitia in intramural hematoma than in dissection, leading to a greater probability of rupture. These results suggest that operation as soon as possible after the onset of intramural hematoma will contribute to improved survival.

Acute Disease↗

Traumatic brain injury and hemorrhagic hypotension suppress neuroprotective gene expression in injured hippocampal neurons.

BACKGROUND: After traumatic brain injury, memory dysfunction is due in part to damage to the hippocampus. To study the molecular mechanisms of this selective vulnerability, the authors used laser capture microdissection of neurons stained with Fluoro-Jade to directly compare gene expression in injured (Fluoro-Jade-positive) and adjacent uninjured (Fluoro-Jade-negative) rat hippocampal neurons after traumatic brain injury and traumatic brain injury plus hemorrhagic hypotension. METHODS: Twelve isoflurane-anesthetized Sprague-Dawley rats underwent moderate (2.0 atm) fluid percussion traumatic brain injury followed by either normotension or hemorrhagic hypotension. Animals were killed 24 h after injury. Frozen brain sections were double stained with 1% cresyl violet and 0.001% Fluoro-Jade. RNA from 10 Fluoro-Jade-positive neurons and 10 Fluoro-Jade-negative neurons, obtained from the hippocampal CA1, CA3, and dentate gyrus subfields using laser capture microdissection, was linearly amplified and analyzed by quantitative ribonuclease protection assay for nine neuroprotective and apoptosis-related genes. RESULTS: In injured CA3 neurons, expression of the neuroprotective genes glutathione peroxidase 1, heme oxygenase 1, and brain-derived neurotrophic factor was significantly decreased compared with that of adjacent uninjured neurons. Superimposition of hemorrhagic hypotension was associated with down-regulation of neuroprotective genes in both injured and uninjured neurons of all subregions. Expression of apoptosis-related genes did not vary between injured and uninjured neurons, with or without superimposed hemorrhage. CONCLUSIONS: The authors show, in the first direct comparison of messenger RNA levels in injured and uninjured hippocampal neurons, that injured neurons express lower levels of neuroprotective genes than adjacent uninjured neurons.

Animals↗

Human corneal endothelial cell precursors isolated by sphere-forming assay.

PURPOSE: To isolate precursors of human corneal endothelial cells (HCECs) in vitro. METHODS: HCECs were subjected to a sphere-forming assay in which spheres floated in serum-free medium containing growth factors. To promote differentiation, the isolated sphere colonies were plated in dishes coated with poly-L-lysine (PLL)/laminin or fetal bovine endothelium extracellular matrix. Marker expression of neural and mesenchymal cells was examined in the sphere colonies and their progenies by immunocytochemistry and/or reverse transcription-polymerase chain reaction (RT-PCR). Adherent differentiated cells from the sphere colonies were evaluated morphologically and functionally. RESULTS: HCECs formed primary and secondary spherical colonies, as shown by sphere-forming assay in vitro. The colonies expressed nestin, beta3-tublin, glial fibrillary acidic protein, and alpha-smooth muscle actin on immunocytochemistry. The progeny, proliferating on extracellular matrix derived from bovine corneal endothelium, but not on PLL/laminin-coated and noncoated dishes, expressed nestin and beta3-tublin. These markers were confirmed by RT-PCR. Adherent differentiated cells from the sphere colonies had an HCEC-like hexagonal shape and satisfactory transport activity that is essential in HCECs. CONCLUSIONS: These findings indicate that the HCEC contains precursor cells with a propensity to differentiate into HCECs and that these cells can also produce neuronal and mesenchymal cell proteins.

Actins↗

Comparison of FDG PET and SPECT for detection of bone metastases in breast cancer.

OBJECTIVE: The purpose of our study was to evaluate the efficacy of FDG PET and bone SPECT for diagnosing bone metastases in breast cancer. SUBJECTS AND METHODS: The study was a prospective series of 15 patients with breast cancer who underwent both PET and bone scanning with SPECT. Comparison was performed on a lesion-by-lesion analysis. MDCT, MRI, and the patient's clinical course were used as references. RESULTS: In the lesion-by-lesion analysis (n = 900), the sensitivity for diagnosing bone metastases was 85% for SPECT and 17% for PET, specificity was 99% for SPECT and 100% for PET, and accuracy was 96% for SPECT and 85% for PET. In the statistical analysis, bone SPECT was significantly superior to FDG PET for its sensitivity (p < 0.0001) and accuracy (p < 0.0001). No statistically significant difference was seen with regard to specificity. When classifying the bone metastases as osteoblastic or osteolytic, bone scanning classified 92% of metastases as osteoblastic and 35% of metastases as osteolytic, whereas PET classified 6% of metastases as osteoblastic and 90% of metastases as osteolytic. CONCLUSION: Bone SPECT is superior to FDG PET in detecting bone metastases in breast cancer. The sensitivity of osteoblastic lesions is limited with FDG PET. Surveillance of metastatic spread to the skeleton in breast cancer patients based on FDG PET alone is not possible.

Adult↗

[Predictive value of coagulative molecular markers for thromboembolism in patients with nonvalvular atrial fibrillation: prospective five-year follow-up study].

OBJECTIVES: Nonvalvular atrial fibrillation is a known risk factor for thromboembolism. This study investigated the use of coagulation markers to predict thromboembolism in nonvalvular atrial fibrillation patients. METHODS: One hundred thirty nonvalvular atrial fibrillation patients (104 males, 26 females, mean age 63.7 +/- 10.7 years) treated at the Sendai Cardiovascular Center from April 1996 to August 1997 were enrolled in this study. Coagulation markers such as prothrombin fragment 1 + 2, thrombin-antithrombin III complex and D-dimer were measured, and the patients were followed up prospectively to October 2001. RESULTS: One hundred and twenty-six patents (100 males, 26 females, chase rate 96.9%) were included in this investigation based on the medical chart and telephone interview. During five-year follow-up, 16 patients had thromboembolism accidents (3.25%/year) and two were suspected to die of thromboembolism. Three patients died of malignant disease, four of heart disease, and five of other diseases. Eight (25.8%) of the 31 patients with high levels of thrombin-antithrombin III complex and 6 (33.3%) of 18 patients with high levels of D-dimer suffered thromboembolism accidents. High thrombin-antithrombin III complex and D-dimer were statistically positive predictive markers for thromboembolism in patients with nonvalvular atrial fibrillation (p < 0.05). CONCLUSIONS: Coagulation markers such as thrombin-antithrombin III complex and D-dimer can predict thromboembolism accidents in nonvalvular atrial fibrillation patients.

Aged↗

Are anemic patients more sensitive to calcineurin inhibitors?

A calcineurin inhibitor (CNI) is characterized by high affinity binding to red blood cells. There is a possibility that hematocrit levels might affect the immunosuppressive effects of cyclosporine (CsA). The purpose of this study was to examine whether the treatment with CNI was more effective in preventing acute rejection in anemic compared with nonanemic patients and to find a suitable method to monitoring immunosuppression. Ninety-five living donor renal transplant recipients who were treated with CsA were divided into five groups depending on their Ht levels. The incidences of biopsy-proven acute rejection were 1/8 (12.5%), 8/31 (25.8%), 6/28 (21.4%), 10/22 (45.5%), and 2/6 (33.3%) for Ht < or = 25%, 25% < Ht < or = 30%, 30% < Ht < or = 35%, 35% < Ht < or = 40%, and 40% < Ht, respectively. In vitro IL-2 mRNA inhibition tests were performed to evaluate lymphocyte function after stimulation of whole-blood with phorbol myristate acetate and Ca-ionophore in the presence of various concentrations of CsA. Whole blood CsA levels causing 50% inhibition of IL-2 mRNA (IC50) were 256, 310, 175, and 55 ng/mL for Ht 50%, 40%, 30%, and 20%, respectively. It is speculated that plasma concentrations of CsA may increase at low Ht levels, because lower incidences of acute rejection and lower IC50 values of CsA were observed in the anemic state. When the dosage of CsA was adjusted to its whole-blood concentration, the anemic state is likely to enhance the immunosuppressive effect of CsA. A pharmacodynamic study, such as the IL-2 mRNA inhibition test, is preferable for CsA monitoring.

Anemia↗

Progressive changes in neurofilament proteins and growth-associated protein-43 immunoreactivities at the site of cervical spinal cord compression in spinal hyperostotic mice.

STUDY DESIGN: Immunohistochemical examination of the expression and localization of neurofilament (NF) proteins and growth-associated protein (GAP)-43 in spinal hyperostotic (twy/twy) mice with progressive compression of the cervical spinal cord. OBJECTIVE: To determine the biologic functions of NF proteins and GAP-43 in the mouse cervical spinal cord during chronic mechanical compression. SUMMARY OF BACKGROUND DATA: The pathologic and repair process in the chronically compressed spinal cord are understood poorly. The present authors hypothesized that there existed an increased expression of NF proteins and GAP-43 in twy/twy mice during the lengthy period of spinal cord compression, which resembles compressive myelopathy. METHODS: The cervical spinal cords of 54 twy mice (aged 8 weeks [n = 18], 14 weeks [n = 18], and 20 weeks [n = 18]) and 18 control animals were examined histologically. Using appropriate antibodies, sections were also stained immunohistochemically for NF proteins and GAP-43. RESULTS: Separation of the myelin sheath from the axon and axonal swelling with deformation were detected in the anterior and lateral funiculi of the spinalcords of 20-week-old twy/twy mice. No such changes were noted in 8-week-old twy mice. In twy/twy mice aged 8 and 14 weeks with mild-to-moderate compression, weak immunoreactivities (mainly in the white matter) for NF proteins and GAP-43 were noted; however, in 20-week-old twy/twy mice, these axons stained strongly positive and immunoreactive swollen axons were present. The relative area of GAP-43 immunoreactive axons gradually increased between 8 and 20 weeks in each column, particularly in the anterior and lateral funiculi in the contralateral side of compression. CONCLUSIONS: The results showed that the expression of NF proteins and GAP-43 in the white matter increased proportionally with the magnitude of spinal cord compression, and indicated the possible involvement of GAP-43 in both axonal degeneration and repair processes in the chronically compressed spinal cord.

Aging↗

Minimized mortality and neurological complications in surgery for chronic arch aneurysm: axillary artery cannulation, selective cerebral perfusion, and replacement of the ascending and total arch aorta.

OBJECTIVE: Cerebral complication is still a major concern in surgery for arteriosclerotic aortic arch disease. For preventing this complication, axillary artery cannulation, selective cerebral perfusion, and replacement of the ascending and arch aorta were applied to thoracic aortic aneurysm involving aortic arch. METHOD: From May 1999 to July 2002, consecutive 39 patients with true aneurysm (29 patients) or chronic aortic dissection (10 patients) involving aortic arch underwent replacement of the ascending and arch aorta with an elephant trunk under hypothermic cardiopulmonary bypass through the axillary artery cannulation and selective cerebral perfusion. The brain was continuously perfused without any intermission through the axillary artery. Concomitant operation included coronary artery bypass grafting (CABG) in two patients, aortic valve replacement (AVR) in one, Bentall operation in two, mitral valve replacement (MVR) in one, and aortic valve sparing operation in one. Patient age at operation was 40-84 (72 + 9) years and 24 of them were older than 70 years of age. RESULTS: There was one operative death (2.5%) due to bleeding from the left lung, and one hospital death due to respiratory failure. Postoperative permanent neurological dysfunction was found in one patient (2.5%). Two patients presented temporary neurological dysfunction (5%). Thirty-six of the 39 patients were discharged from hospital on foot. CONCLUSION: Continuous perfusion through the axillary artery with selective cerebral perfusion and replacement of the ascending and arch aorta may minimize cerebral complication leading to satisfactory results in patients with chronic aortic aneurysm involving aortic arch.

Adult↗

Progression of esophageal carcinoma by loss of EGF-STAT1 pathway.

PURPOSE: In only a very limited number of cultured cell lines, epidermal growth factor (EGF), a potent mitogen for many kinds of cells, was shown to activate STAT1 (signal transducer and activator of transcription 1) protein, which can transmit signals that cause cell growth arrest and apoptosis. The purpose of this work is to elucidate the physiologic and/or pathological significance of this EGF-STAT1 pathway. MATERIALS AND METHODS: A series of cultured cell lines that had been established from surgical specimens of esophageal squamous cell carcinoma was studied for the existence of the EGF-STAT1 pathway. Normal esophageal squamous epithelial cells either explanted from non-neoplastic portions of surgically removed human esophageal tissue or in bovine esophageal epithelium in situ were examined as well. RESULTS: EGF treatment leads to a strong growth arrest in three of the 30 esophageal squamous cell carcinoma cell lines. STAT1 was found to be activated by EGF in the three cell lines but not in the others. EGF can also activate STAT1 in cultured normal esophageal squamous epithelial cells. STAT1 is at the activated state in the basal cell layer of the bovine esophageal epithelium. Notably, patients who had harbored the cancer cells with the EGF-STAT1 pathway had a dramatically better prognosis. DISCUSSION: The EGF-STAT1 pathway may be intrinsic to esophageal epithelial lineage of cells and is lost in a considerable fraction of the carcinomas. This loss appears to cause a significantly more malignant clinical course. These findings may point out a critical step in the progression of esophageal cancer and could lead to the development of useful clinical applications.

Blotting, Northern↗

Evidence that donor pretreatment with FK506 has a synergistic effect on graft prolongation in hamster-to-rat heart xenotransplantation.

BACKGROUND: Concordant xenografts are rejected in a different fashion than are discordant xenografts or allografts. We tested the effect of donor pretreatment with the use of FK506 combined with posttransplantation FK506 treatment and splenectomy and analyzed the mechanism of rejection in hamster-to-rat heart xenotransplantation. METHODS: Heart xenotransplantation from hamster to rat was carried out under immunosuppression with the use of donor pretreatment with FK506, posttransplantation FK506 treatment and splenectomy, followed by complement-dependent cytotoxicity assay, delayed type hypersensitivity test, and histologic analysis. RESULTS: The cardiac graft survived 3 days without donor pretreatment, whereas it survived 4.8 days with donor pretreatment with FK506 (5 mg/kg for 3 days). The graft survival was synergistically enhanced by donor pretreatment, posttransplantation FK506 therapy, and splenectomy, and the longest survival was 43.6 +/- 7.7 days in the group with donor pretreatment, posttransplantation FK506 therapy for 4 weeks, and splenectomy. Delayed-type hypersensitivity response was suppressed significantly in the donor pretreatment group. The antibody typed by immunoglobulin M was mainly detected in the rat serum with the rejected grafts by complement-dependent cytotoxicity assay. Correlating with this complement-dependent cytotoxicity titer, neutrophil infiltration and vasculitis of the coronary vessels were recognized in the rejected grafts, and the marginal zone of the white pulp expanded in the spleen. CONCLUSIONS: Donor pretreatment with FK506 combined with posttransplantation FK506 therapy and splenectomy suppresses the outlet antigen, immunoglobulin M production, and lymphocyte activation, thereby prolonging the graft survival in hamster-to-rat heart xenotransplantation.

Animals↗

Estrogen receptor beta is expressed in human stomach adenocarcinoma.

PURPOSE: In stomach adenocarcinoma, the role of the hormonal receptor, estrogen receptor (ER), has been controversial. Recently, a new estrogen receptor, called estrogen receptor beta (ER beta), was found to be expressed in various tissues including normal gastrointestinal tract. In this paper, the expression of ER beta in stomach adenocarcinomas has been investigated for the first time, specifically in signet ring cell adenocarcinomas, together with surrounding non-cancerous tissues. METHODS: By immunohistochemistry the expression of ER alpha and beta was studied in 29 stomach adenocarcinomas, ten signet ring cell adenocarcinomas, and 19 other adenocarcinomas. Western blotting was performed to examine the immunohistochemical result. Statistical studies (Student's t test and chi(2)-test) explored the relation between the immunohistochemical result and clinicopathological characteristics. RESULTS: All 29 adenocarcinomas, including the signet ring cell ones, demonstrated clear ER beta nucleus staining. Lymphocytes, venous endothelial cells, smooth muscle, and non-cancerous stomach glands also showed strong ER beta staining, while no staining was observed in the immunohistochemistry of ER alpha. Western blotting showed equivalent ER beta protein levels in cancerous and non-cancerous tissues, which was consistent with the results of immunohistochemical staining. Among signet ring cell adenocarcinomas of the stomach, cytoplasm were stained in addition to nuclei, specifically in patients under the age of 40 years. CONCLUSIONS: Our results imply that the effects of estrogen in stomach cancer, as well as those in normal stomach, may be mediated by ER beta, and that the role of ER beta may differ by the subtype of stomach adenocarcinoma - specifically signet ring cell adenocarcinomas and other ones - although large scale samples are needed to confirm these findings.

Adenocarcinoma↗

Simple and specific assessment of Ca-entry-blocking activities of drugs by measurement of Ca reversal.

A new, simple, and specific screening method for Ca-entry blocker is reported. In the presence of various blockers of Ca-entry (Ca-channel blockers), Ca2+ (1 x 10(-4) M) causes Ca reversal, i.e., it causes relaxation of rat uterine smooth muscle that has been tonically contracted with oxytocin in Ca-free medium (Ca-free contraction) after prolonged preincubation with 3 mM EGTA. The potencies of various drugs to cause Ca reversal, assessed on an all-or-none basis, were found to reflect their activities of blocking Ca entry. The potencies of drugs for blocking Ca entry via voltage-operated Ca-channels could be determined in 125.6 mM K+ Ca-free medium. Drugs that inhibited Ca-free contraction directly have some other antispasmodic activity. Conventionally, activity for blocking Ca entry is screened by measuring inhibition of Ca-induced contraction, but true Ca-entry blocking activity cannot be differentiated clearly from other antispasmodic activity when a drug has both activities. However, by measuring Ca reversal, activity for blocking Ca entry only can easily be found, when done in solution with high K+ content for blocking voltage-operated channels and when done in solution with normal K+ content for blocking voltage-independent channels.

Animals↗

Synthesis, structure, and H2O2-dependent catalytic functions of disulfide-bridged dicopper(I) and related thioether-copper(I) and thioether-copper(II) complexes.

A disulfide-bridged dicopper(I) complex, [Cu2(Py2SSPy2)](ClO4)2 (1) (Py2SSPy2 = bis(2-[N,N-bis(2-pyridylethyl)-amino]-1,1- dimethylethyl)disulfide), a thioether-copper(I) complex, [Cu(iPrSPy2)](ClO4) (2) (iPrSPy2 = N-(2-isopropylthio-2-methyl)propyl-N,N-bis-2-(2-pyridyl)ethylamine, and a thioether-copper(II) complex, [Cu-(PheSPy2)(H2O)](ClO4)2 (3) (PheSPy2 = N-(2-methyl-2-phenethylthio)propyl-N,N-bis-2-(2- pyridyl)ethylamine), were newly synthesized by the reactions of Cu(ClO4)2.6H2O with a thiol ligand of Py2SH (N,N-bis[2-(2-pyridyl)-ethyl]-1,1-dimethyl-2- mercaptoethylamine) and thioether ligands of iPrSPy2 and PheSPy2, respectively. For complexes 1 and 2, X-ray analyses were performed. Complex 1 crystallizes in the triclinic space group P1, and complex 2 crystallizes in the orthorhombic space group Pbca with the following unit cell parameters: for 1, a = 15.165 (3) A, b = 22.185 (4) A, c = 14.989 (3) A, alpha = 105.76 (1) degrees, beta = 90.82 (2) degrees, gamma = 75.23 (1) degrees, and Z = 2; for 2, a = 17.78 (2) A, b = 17.70 (1) A, c = 15.75 (1) A, and Z = 8. Complex 1 is the first structurally characterized example obtained by the redox reaction Cu(II) + RSH-->Cu(I) + RSSR and has two independent structures (1a, 1b) which mainly differ in S-S bond distances, Cu(I)...Cu(I) separations, and C-S-S-C dihedral angles of the disulfide units. The S-S bond distances of 2.088(7) A in 1a and 2.070(7) A in 1b are indicative of significant activation of the S-S bonds by the dicopper centers. Fragment molecular orbital (FMO) analyses and molecular orbital overlap population (MOOP) analyses based on the extended Hückel method clarify the preferable formation of the disulfide S-S bond in 1 rather than the formation of a thiolate-copper(II) complex within the Py2S- ligand framework. Catalytic functions of complexes 1-3 were investigated with peroxides (H2O2 and tBuOOH) as oxidants. Complex 1 catalyzed the selective oxidation of cyclohexane to cyclohexanol and mediated the cyclohexene epoxidation in the presence of H2O2. A transient dark green intermediate observed in the reaction of 1 with H2O2 is characterized by UV-vis, EPR, and resonance Raman spectroscopies, identifying it as a Cu(II)-OOH species, 1(OOH). The resonance Raman features of the nu(O-O) bands at 822 and 836 cm-1, which are red-shifted to 781 and 791 cm-1, respectively, upon introduction of H2(18)O2, are indicative of formation of two kinds of Cu-OOH species rather than the Fermi doublet and the significant weakening of the O-O bonds. These mechanistic studies demonstrate that by virtue of the electron-donating ability of the disulfide unit the Cu-OOH species can be actually activated for one-electron oxidation, which has been reported so far unfavorable for other vibrationally characterized Cu-OOH species.

Journal Article↗

Lymphoid apoptosis in acute canine distemper.

The relationship between the canine distemper virus (CDV) infection and apoptosis in the canine lymphoid tissues was investigated using immunostaining for single stranded DNA (ssDNA), TdT-mediated dUTP-biotin nick end-labeling (TUNEL) method, and electron microscopy. Twenty-six lymphoid tissues from 8 spontaneously CDV-infected dogs and 1 non-infected dog were used, and lesions were classified into 4 groups according to frequency of the CDV-antigen. Histologically, the degree of lymphoid depletion tended to depend on amount of CDV antigen. The numbers of ssDNA- and TUNEL-labeling cells were significantly high in the lymphoid tissues with abundant viral antigen. However, ssDNA- and TUNEL-positive lymphocytes were also frequently found even in the lymphoid tissues where there was only a small amount of CDV-antigen in sinus histiocytes. The incidence and distribution of apoptotic cells in the CDV-antigens-negative lymphoid tissues from infected dogs were equal to those from a non-infected dog. Double labeling immunostaining using a ssDNA and a CDV nucleocapsid protein (CDV-NP) antibody revealed that there were ssDNA positive but CDV-NP negative cells besides those stained doubly positive. Ultrastructurally, lymphocytes in the CDV-infected lymphoid tissues frequently had characteristic morphological features of apoptosis such as apoptotic bodies. All these results suggest that CDV leads to lymphocytic apoptosis directly or indirectly, resulting in severe lymphoid depletion and immunosuppression in acute or subacute phase of CDV infection.

Animals↗