The toxicity of dioxins such as 2,3,7,8-tetrachlorodibenzo-
p-dioxin (TCDD) is mainly mediated by the aryl hydrocarbon receptor (AHR), which regulates the multiple target genes including cytochrome ...P4501A (CYP1A). In general, bony fishes, which possess at least two distinct AHRs are one of the most sensitive vertebrates to TCDD in early life stage. However, the physiological and toxicological roles of piscine multiple AHRs are not fully understood, especially in marine fish. To understand which AHR is responsible for TCDD toxicity in a marine fish species, we characterized the early life stage toxicity related to the expression of AHRs and CYP1A in red seabream (
Pagrus major). The embryos at 10
h post-fertilization (hpf) were treated with 0–100
μg/L TCDD for 80
min waterborne exposure. TCDD dose-dependently elicited developmental toxicities including mortality, yolk sac edema, retarded body growth, spinal deformity, reduced heart rate, shortened snout, underdeveloped fin, heart, and lower jaw. Intriguingly, hemorrage and pericardium edema, typical TCDD developmental defects noticed in other fish species, were not found in red seabream until test termination. The EC
egg50
s for yolk sac edema, underdeveloped fin, and spinal deformity were 170, 240, and 340
pg/g, respectively. The LC
egg50 was 360
pg/g embryo, indicating that this species is one of the most sensitive fishes to TCDD toxicity. The expression levels of rsAHR1, rsAHR2 and CYP1A mRNAs were also determined in different developmental stages. The rsAHR2 mRNA expression dose-dependently increased following TCDD exposure, while rsAHR1 mRNA level was not altered. Level of rsAHR2 mRNA measured by two-step real-time PCR was 30 times higher than rsAHR1 in embryos treated with the highest dose. Temporal patterns of rsAHR2 and CYP1A mRNAs were similar in TCDD-treated embryos, representing a significant positive correlation between rsAHR2 and CYP1A mRNA levels, but not between rsAHR1 and CYP1A. In comparison of temporal trends of TCDD-induced AHRs and CYP1A expression, and developmental toxicities, the highest expression of rsAHR2 and CYP1A mRNA were detected prior to the appearance of maximal incidence of TCDD toxic manifestations. These results suggest that rsAHR2 may be dominantly involved in the transcriptional regulation of CYP1A, and several TCDD defects are dependent on the alteration of rsAHR2 and/or rsAHR2-CYP1A signaling pathway that is controlled through their expression levels.
A bioartificial pancreas in which islets of Langerhans (islets) are encapsulated within a semipermeable membrane, such as agarose, has been proposed for treating type I diabetic mellitus. However, ...the long-term storage for providing a convenient and easily accessible supply still remains an issue. We investigated cryopreservation as a potential method of long-term storage for agarose-encapsulated islets (Mic-islets).
The morphology, insulin secretion, and histochemical staining of cryopreserved Mic-islets were analyzed. Streptozotocin-induced diabetic mice were transplanted intraperitoneally with 1000, 2000, and 3000 Mic-islets after cryopreservation in KYO-1 vitrification solution. Blood glucose levels were measured and immunohistochemical analyses were performed at 41 days posttransplantation.
Transplanted cryopreserved Mic-islets restored normoglycemia in diabetic mice. The mean (+/-SD) normoglycemic periods were 32.0+/-13.2 days and 46.3+/-13.3 days for recipients of 1000 (n=5) and 2000 (n=4) cryopreserved Mic-islets, respectively, whereas the mean normoglycemic period was 53.2+/-16.7 days for recipients of 1000 noncryopreserved Mic-islets (n=7). These data indicate that cryopreserved Mic-islets transplanted as a bioartificial pancreas successfully controlled blood glucose levels for extended periods.
Cryopreserved agarose-encapsulated islets could successfully control the blood glucose level for a long period as a bioartificial pancreas.
Adrenomedullin (AM) is a novel vasodilating peptide involved in the regulation of circulatory homeostasis and implicated in the pathophysiology of cardiovascular disease. We tested the hypothesis ...that AM also possesses angiogenic properties. Using laser Doppler perfusion imaging, we found that AM stimulated recovery of blood flow to the affected limb in the mouse hind-limb ischemia model. AM exerted this effect in part by promoting expression of vascular endothelial growth factor (VEGF) in the ischemic limb, and immunostaining for CD31 showed the enhanced flow to reflect increased collateral capillary density. By enhancing tumor angiogenesis, AM also promoted the growth of subcutaneously transplanted sarcoma 180 tumor cells. However, heterozygotic AM knockout mice (AM+/-) showed significantly less blood flow recovery with less collateral capillary development and VEGF expression than their wild-type littermates. Similarly, mice treated with AM22-52, a competitive inhibitor of AM, showed reduced capillary development, and growth of sarcoma 180 tumors was inhibited in AM+/- and AM22-52-treated mice. Notably, administration of VEGF or AM rescued blood flow recovery and capillary formation in AM+/- and AM22-52-treated mice. In cocultures of endothelial cells and fibroblasts, AM enhanced VEGF-induced capillary formation, whereas in cultures of endothelial cells AM enhanced VEGF-induced Akt activation. These results show that AM possesses novel angiogenic properties mediated by its ability to enhance VEGF expression and Akt activity. This may make AM a useful therapeutic tool for relieving ischemia; conversely, inhibitors of AM could be useful for clinical management of tumor growth.
Abstract Bioartificial pancreas in which islets of Langerhans (islets) are enclosed in a semipermeable membrane is one of the approaches to treat insulin-dependent diabetic patients. Although there ...are advantages in this method, one of the issues that still remains is the long-term storage of tissue engineering devices before transplantation. One of the possible routes to address this is through cryopreservation. In this study, a freezing solution, 2 m DMSO in RPMI-1640, a conventional vitrification solution, VS55, and the newly developed vitrification solution KYO-1 were examined to cryopreserve microencapsulated islets in agarose hydrogel. The insulin release ability, morphology of islets, and physico-chemical properties of the agarose gel membrane were examined after a cryopreservation and thawing process. Frozen and vitrified (by KYO-1) groups showed a similar insulin secretion. Frozen groups by 2 m DMSO, however, showed destruction of agarose capsules and some islets were out of the capsule. When KYO-1 was used, islets still maintained the ability to release insulin in response to glucose stimulation, and agarose capsule showed morphological integrity, and mechanical properties. In conclusion, vitrification using KYO-1 which is composed of 5.38 m ethylene glycol, 2 m DMSO, 0.1 m PEG 1000 and 0.00175 m PVP K10 in EuroCollins, is a suitable method for cryopreservation of microencapsulated islets.
We conducted diallel analyses of root shape and size In Japanese radish to determine the interaction between genetic effects and soil type in the selection for these traits in a breeding program. A ...set of diallel crosses of six inbred lines was grown in an andosol, a clayey soil and a sandy soil. The major shape characteristics accounted for by the principal components of elliptic Fourier descriptors were the ratio of length to width, the bluntness of the distal part, the curvature of the central part, and the curvature of the proximal and distal parts. Analysis of variance of diallel tables showed that the genetic effects were highly significant for all the characteristics. In contrast, the influence of the soil type was markedly different among the characteristics. Soil type effect was significant for size characteristics and the bluntness of the distal part. In the bluntness of the distal part, the interaction between genetic effects and soil type was significant, and the heritability and the degree of dominance varied between the soil types. The results indicated that the differences in the soil types did not Influence the selection for the root size or shape in most characteristics. However, the interaction between genetic effects and soil type should be taken into account in the selection for the bluntness of the distal part.
In the conservation and management practices of natural forests, sound reproduction and regeneration form the basis of the maintenance and viability of the tree populations. To obtain and serve ...biological information for sustainable forest management, we investigated reproductive biology and inbreeding depression in seeds of an important dipterocarp tree species,
Shorea acuminata (Dipterocarpaceae), by both field and laboratory experiments. Results of parental analysis of immature and mature seeds showed that selfing rates varied greatly, from 7.6 to 88.4% among eight mother trees, and the mean overall selfing rate was 38.3%. Observed outcrossing events within a 40-ha study plot were predominantly (76.5%) short-distance events with a mating distance (md)
≤
100
m. Since the selfing rate sharply decreased with increase in the number of flowering conspecifics (i.e., individuals of the same species) within a 100-m radius from the mother trees, the local density of flowering conspecifics appears to be the key factor determining the outcrossing rate in
S. acuminata. However, the extremely high selfing rate (88.4%) observed for one tree could not be simply explained by the low local density of flowering conspecifics. Instead, differences in its flowering phenology (its flowering peaked
ca. a week earlier than most of the other examined individuals) may have severely limited its receipt of pollen from other conspecifics, and thus promoted selfing. Since there were no significant differences in the proportion of selfed progeny between immature and mature seed stages, there was no evidence of selective abortion of selfed seeds during seed development. However, the seed mass of outcrossed progeny was heavier than that of selfed progeny, and heavier seeds showed higher success rates at germination and seedling establishment. These results suggest that inbreeding depression resulted in reductions in seed mass and may reduce the fitness of selfed seeds in
S. acuminata. In addition, the outcrossing rate of
S. acuminata was more sensitive to low local conspecific flowering-tree densities than that of a sympatric bee-pollinated dipterocarp species with greater pollination distances. These results suggest that the management of local adult-tree densities is important for avoiding selfing and inbreeding depression in future generations, especially in a species like
S. acuminata with predominantly short-distance pollination.
To elucidate the role of genetic factors in arsenic (As) metabolism, we studied associations of single nucleotide polymorphisms (SNPs) in As (+
3 oxidation state) methyltransferase (
AS3MT) with the ...As concentrations in hair and urine, and urinary As profile in residents in the Red River Delta, Vietnam. Concentrations of total As in groundwater were 0.7–502 μg/l. Total As levels in groundwater drastically decreased by using sand filter, indicating that the filter could be effective to remove As from raw groundwater. Concentrations of inorganic As (IAs) in urine and total As in hair of males were higher than those of females. A significant positive correlation between monomethylarsonic acid (MMA)/IAs and age in females indicates that older females have higher methylation capacity from IAs to MMA. Body mass index negatively correlated with urinary As concentrations in males. Homozygote for SNPs 4602AA, 35991GG, and 37853GG, which showed strong linkage disequilibrium (LD), had higher percentage (%) of dimethylarsinic acid (DMA) in urine. SNPs 4740 and 12590 had strong LD and associated with urinary %DMA. Although SNPs 6144, 12390, 14215, and 35587 comprised LD cluster, homozygotes in SNPs 12390GG and 35587CC had lower DMA/MMA in urine, suggesting low methylation capacity from MMA to DMA in homo types for these SNPs. SNPs 5913 and 8973 correlated with %MMA and %DMA, respectively. Heterozygote for SNP 14458TC had higher MMA/IAs in urine than TT homozygote, indicating that the heterozygote may have stronger methylation ability of IAs. To our knowledge, this is the first study on the association of genetic factors with As metabolism in Vietnamese.
Endotracheal/endobronchial metastases (EEMs) from nonpulmonary neoplasms are rare. However, their definition and developmental modes have not yet been fully elucidated.
EEMs were defined as ...documented nonpulmonary neoplasms metastatic to the subsegmental or more proximal central bronchus, in a bronchoscopically visible range. The clinical and pathologic features of 16 cases were reviewed, with special emphasis on the developmental modes based on five criteria: location in the tracheobronchial tree, number of lesions, laterality of lesions, depth of lesions, and relationship with the associated bronchus.
The developmental modes were proposed on the basis of the above five criteria as follows: type I, direct metastasis to the bronchus; type II, bronchial invasion by a parenchymal lesion; type III, bronchial invasion by mediastinal or hilar lymph node metastasis; and type IV, peripheral lesions extended along the proximal bronchus. Primary tumors included colorectal in six patients, breast in three patients, uterus in two patients, osteosarcoma of the bone in two patients, and maxillary, larynx, and parotid carcinoma in one patient each, respectively. The mean recurrence interval was 65.3 months. The developmental modes were as follows: type I, five patients; type II, one patient; type III, four patients; and type IV, nine patients. Three patients underwent surgical resection. One patient has remained well for 5 years after operation. Median and mean survival times were 9 months and 15.5 months, respectively.
The mean recurrence interval was long at 65.3 months, but the mean survival time was short at 15.5 months. Type I accounted for only 5 of 16 patients. Type II was found in only one patient. It is thought that this type is a rare form. Type IV affected nine patients. Treatment plans must be individualized, because in some cases, long-term survival can be expected.
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