A preliminary feasibility study of simultaneous dual-isotope imaging with a solid-state dedicated cardiac camera for evaluating myocardial perfusion and fatty acid metabolism

Simultaneous dual-isotope SPECT imaging with 201Tl and ¹²³I-β-methyl-p-iodophenylpentadecanoic acid (BMIPP) is used to study the perfusion–metabolism mismatch. It predicts post-ischemic functional recovery by detecting stunned myocardium. On the other hand, ^99mTc-MIBI is another radioisotope widely used in myocardial perfusion imaging because of its better image quality and lower radiation exposure than 201Tl. However, since the photopeak energies of ^99mTc and ¹²³I are very similar, crosstalk hampers the simultaneous use of these two radioisotopes. To overcome this problem, we conducted simultaneous dual-isotope imaging study using the D-SPECT scanner (Spectrum-Dynamics, Israel) which has a novel detector design and excellent energy resolution. We first conducted a basic experiment using cardiac phantom to simulate the condition of normal perfusion and impaired fatty acid metabolism. Subsequently, we prospectively recruited 30 consecutive patients who underwent successful percutaneous coronary intervention for acute myocardial infarction, and performed ^99mTc-MIBI/¹²³I-BMIPP dual-isotope imaging within 5 days after reperfusion. Images were interpreted by two experienced cardiovascular radiologists to identify the infarcted and stunned areas based on the coronary artery territories. As a result, cardiac phantom experiment revealed no significant crosstalk between ^99mTc and ¹²³I. In the subsequent clinical study, ^99mTc-MIBI/¹²³I-BMIPP dual-isotope imaging in all participant yielded excellent image quality and detected infarcted and stunned areas correctly when compared with coronary angiographic findings. Furthermore, we were able to reduce radiation exposure to significantly approximately one-eighth. In conclusion, we successfully demonstrated the practical application of simultaneous assessment of myocardial perfusion and fatty acid metabolism by ^99mTc-MIBI and ¹²³I-BMIPP using a D-SPECT cardiac scanner. Compared with conventional ²⁰¹TlCl/¹²³I-BMIPP dual-isotope imaging, the use of ^99mTc-MIBI instead of ²⁰¹TlCl improves image quality as well as lowers radiation exposure.     

Dynamic changes in intranuclear and subcellular localizations of mouse Prrp/DAZAP1 during spermatogenesis: the necessity of the C-terminal proline-rich region for nuclear import and localization

Mouse Prrp (mPrrp)/DAZAP1 is a mouse ortholog of Xenopus Prrp, which is involved in vegetal pole localization of Vg1 mRNA in oocytes and is highly expressed in the testis. The mouse protein has been reported to be a shuttling protein which localizes in the nucleus of pre-meiotic spermatogenic cells and round spermatids, and shifts its location into the cytoplasm in elongating spermatids, suggesting that mPrrp may be involved in mRNA transport as well as that of the Xenopus ortholog. We reexamined immunohistochemical analyses of mPrrp/DAZAP1 during spermatogenesis utilizing a newly established monoclonal antibody and reconfirmed it to be a shuttling protein. We also carried out new observations that included remarkable intranuclear movement during spermatogenesis. In addition, we found that a long amino acid stretch which spanned over the C-terminal half of the protein was required for the nuclear import. These observations demonstrated dynamic changes in subnuclear and subcellular localization which might reflect specific functions during spermatogenesis.     

Fecal microflora in a patient with short-bowel syndrome and identification of dominant lactobacilli.

Fecal microflora and lactate concentrations in blood and feces obtained from a patient (a 5 year-old boy) with short-bowel syndrome (SBS) were compared during acidosis to results for the normal condition (no SBS symptoms). The taxonomical position of the lactobacilli found predominantly in the feces sample obtained 2 days before the fifth attack was also studied. The D-lactate level in serum obtained 1 day after the fourth attack was 10-fold higher than that for the normal condition, although there was not a great difference in L-lactate levels. D-Lactate (3.91 mM) and L-lactate (2.86 mM) were also detected in the feces samples collected 2 days before the fifth attack, while no lactate was detected in the feces sample for the normal condition. The counts of total fecal bacteria, especially anaerobic bacteria such as members of the family Bacteroidaceae, were found to be low. The counts of lactobacilli and the total population of lactobacilli relative to total fecal bacteria in the feces 2 days before the fifth attack (40.4%) were extremely high. In this case, a majority of the lactobacilli were D-lactate producers as determined by homolactic fermentation. These lactobacilli were identified as Lactobacillus delbrueckii subsp. lactis. The percentages of bifidobacteria relative to total fecal bacteria in feces samples obtained both 2 days before the fifth attack (50.9%) and for normal condition (61.9%) were also high, although these bacteria were L-lactate producers. In the feces samples for the normal condition, the D-lactate producers decreased to less than 10(9) per g, while the counts of L- or DL-lactate producers were 100-fold higher than the numbers in feces samples obtained 2 days before the fifth attack. These results suggested that an increase in the level of D-lactate producers, such as L. delbrueckii subsp. lactis, in the colon may be associated with the clinical expression of metabolic acidosis.     

Age-related severity of dopaminergic neurodegeneration to MPTP neurotoxicity causes motor dysfunction in C57BL/6 mice

This study investigated the influence of advancing age on dopaminergic neuronal degeneration induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication from the perspective concerning the relationship between dopaminergic function and behavioral features. Young (10 weeks) and older (14-15 months) C57BL/6 mice were treated with one to four injections of MPTP (20 mg/kg at 2h intervals). Although young mice showed no mortality in either MPTP treatment, older mice exhibited mortality from only two injections of MPTP during the experimental period. An extensive dopaminergic cell loss was found in both the striatum and substantia nigra of older mice given one and two injections of MPTP with marked decrease in striatal dopamine (DA) levels, but not young mice. We also found a behavioral change in the tail suspension test associated with the extent of decrease in striatal DA levels in MPTP-treated older mice, but not in young mice. These results clearly present age-related vulnerability to MPTP neurotoxicity in C57BL/6 mice and strongly support our previous report showing that there is a critical threshold level of the decrement in striatal DA contents causing motor dysfunction in this mouse model of Parkinson's disease.     

53BP1 contributes to survival of cells irradiated with X-ray during G1 without Ku70 or Artemis

Ionizing radiation (IR) induces a variety of DNA lesions. The most significant lesion is a DNA double-strand break (DSB), which is repaired by homologous recombination or nonhomologous end joining (NHEJ) pathway. Since we previously demonstrated that IR-responsive protein 53BP1 specifically enhances activity of DNA ligase IV, a DNA ligase required for NHEJ, we investigated responses of 53BP1-deficient chicken DT40 cells to IR. 53BP1-deficient cells showed increased sensitivity to X-rays during G1 phase. Although intra-S and G2/M checkpoints were intact, the frequency of isochromatid-type chromosomal aberrations was elevated after irradiation in 53BP1-deficient cells. Furthermore, the disappearance of X-ray-induced gamma-H2AX foci, a marker of DNA DSBs, was prolonged in 53BP1-deficient cells. Thus, the elevated X-ray sensitivity in G1 phase cells was attributable to repair defect for IR-induced DNA-damage. Epistasis analysis revealed that 53BP1 plays a role in a pathway distinct from the Ku-dependent and Artemis-dependent NHEJ pathways, but requires DNA ligase IV. Strikingly, disruption of the 53BP1 gene together with inhibition of phosphatidylinositol 3-kinase family by wortmannin completely abolished colony formation by cells irradiated during G1 phase. These results demonstrate that the 53BP1-dependent repair pathway is important for survival of cells irradiated with IR during the G1 phase of the cell cycle.     

Malignant transformation of mature cystic teratoma to squamous cell carcinoma involves altered expression of p53‐ and p16/Rb‐dependent cell cycle regulator proteins

Ovarian mature cystic teratomas (MCT) uncommonly undergo malignant transformation to squamous cell carcinoma (SCC). While alterations in the p53 tumor suppressor gene and protein have been shown, few studies have analyzed other molecular changes leading to this malignant conversion. The purpose of the present study was to investigate 21 samples of SCC arising in MCT for altered expression in known p53‐ and p16/Rb‐dependent cell cycle regulatory proteins, and the association between their expression and cellular proliferation and histological features. Overexpression of the p53 protein was observed in 14 SCC (67%), while four (19%) had point mutations in the p53 gene. Reduced expression of the p16 protein was observed in 18 SCC (86%), while p16 gene alterations (hypermethylation (29%) and point mutation (33%)) were found in 11 (52%). Furthermore, a statistically significant correlation was observed between p53 and Rb overexpression (P = 0.0010), and the overexpression of both p53 and Rb was respectively significantly correlated with increased cellular proliferation. The results indicate that alterations in both the p53 and p16‐Rb pathways are associated with SCC arising in MCT.     

The induced RNA‐binding protein,HuR, targets 3′‐UTR region of IL‐6 mRNA and enhances its stabilization in periodontitis

RNA‐binding proteins (RBPs) regulate mRNA stability by binding to the 3′‐untranslated region (UTR) region of mRNA. Human antigen‐R (HuR), one of the RBPs, is involved in the progression of diseases, such as rheumatoid arthritis, diabetes mellitus and some inflammatory diseases. Interleukin (IL)‐6 is a major inflammatory cytokine regulated by HuR binding to mRNA. Periodontal disease (PD) is also an inflammatory disease caused by elevations in IL‐6 following an infection by periodontopathogenic bacteria. The involvement of HuR in the progression of PD was assessed using in‐vitro and in‐vivo experiments. Immunohistochemistry of inflamed periodontal tissue showed strong staining of HuR in the epithelium and connective tissue. HuR mRNA and protein level was increased following stimulation with Porphyromonas gingivalis (Pg), one of the periodontopathogenic bacteria, lipopolysacchride (LPS)‐derived from Pg (PgLPS) and tumour necrosis factor (TNF)‐α in OBA‐9, an immortalized human gingival epithelial cell. The luciferase activity of 3′‐UTR of IL‐6 mRNA was increased by TNF‐α, Pg and PgLPS in OBA‐9. Luciferase activity was also increased in HuR‐over‐expressing OBA‐9 following a bacterial stimulation. Down‐regulation of HuR by siRNA resulted in a decrease in mRNA expression and production of IL‐6. In contrast, the over‐expression of HuR increased IL‐6 mRNA expression and production in OBA‐9. The HuR inhibitor, quercetin, suppressed Pg‐induced HuR mRNA expression and IL‐6 production in OBA‐9. An oral inoculation with quercetin also inhibited bone resorption in ligature‐induced periodontitis model mice as a result of down‐regulation of IL‐6. These results show that HuR modulates inflammatory responses by regulating IL‐6.     

Clinical and genetic characteristics of Stargardt disease in a large Western China cohort: Report 1

Stargardt disease 1 (STGD1) is the most prevalent retinal dystrophy caused by pathogenic biallelic ABCA4 variants. Forty‐two unrelated patients mostly originating from Western China were recruited. Comprehensive ophthalmological examinations, including visual acuity measurements (subjective function), fundus autofluorescence (retinal imaging), and full‐field electroretinography (objective function), were performed. Next‐generation sequencing (target/whole exome) and direct sequencing were conducted. Genotype grouping was performed based on the presence of deleterious variants. The median age of onset/age was 10.0 (5–52)/29.5 (12–72) years, and the median visual acuity in the right/left eye was 1.30 (0.15–2.28)/1.30 (0.15–2.28) in the logarithm of the minimum angle of resolution unit. Ten patients (10/38, 27.0%) showed confined macular dysfunction, and 27 (27/37, 73.7%) had generalized retinal dysfunction. Fifty‐eight pathogenic/likely pathogenic ABCA4 variants, including 14 novel variants, were identified. Eight patients (8/35, 22.8%) harbored multiple deleterious variants, and 17 (17/35, 48.6%) had a single deleterious variant. Significant associations were revealed between subjective functional, retinal imaging, and objective functional groups, identifying a significant genotype–phenotype association. This study illustrates a large phenotypic/genotypic spectrum in a large well‐characterized STGD1 cohort. A distinct genetic background of the Chinese population from the Caucasian population was identified; meanwhile, a genotype–phenotype association was similarly represented.     

New variant groups identified from HGV isolates

Summary.  We have determined the primary sequence of the 5^′ noncoding region (5^′ NCR) and putative helicase regions (NS-3) of hepatitis G virus (HGV) and GB virus C (GBV-C) that were isolated in Japan from suspected cases of nonA-nonB and/or nonA-nonB-nonC viral hepatitis by using RT-PCR, and we compared the newly isolated sequences with three established isolates. The addition of a "G" residue was found at the 5^′ terminus of all 8 Japanese isolates. These isolates were more clearly distinguished from the prototype viruses by comparison with the 5^′ NCR sequence than by comparison with the NS-3 region. Our results suggested that at least three distinct genomic variants of HGV exist. Genotyping of HGV by using RT-PCR based on the sequence of the 5^′ NCR seems highly feasible. Accepted November 18, 1996 Received September 11, 1996     

Odor discrimination of "IP 3-" and “cAMP-increasing” odorants in the turtle olfactory bulb

The ability of the turtle olfactory system to discriminate between various odorants that increase levels of adenosine 3′,5′-cyclic monophosphate (cAMP) and inositol trisphosphate (IP ₃) in the olfactory bulb was examined by the cross-adaptation technique and analyzed by multidimensional scaling. The mean values of the degree of discrimination among the IP ₃-increasing odorants were higher than those among the cAMP-increasing odorants, and were similar to those between cAMP- and IP ₃-increasing odorants, suggesting that the features of the receptors of cAMP-increasing odorants are different from those which respond to IP ₃-increasing odorants. Analysis by multidimensional scaling suggested that differences in second messenger pathways are not related to detecting odor quality in the turtle olfactory system. Received: 21 July 1995/Received after revision: 20 October 1995/Accepted: 6 November 1995