Structure and sequence of the mouse V1a and V1b vasopressin receptor genes

The structural organization and 5'-flanking region of the mouse V1a and V1b vasopressin receptor genes were determined. The mouse V1a receptor gene was located within an 8-kb XbaI fragment, and the mouse V1b receptor gene was located within a 14-kb EcoRV fragment. Both genes were comprised of two coding exons that were separated by a 2.3-kb and a 8.0-kb intron, respectively, located before the respective seventh transmembrane domain of the receptor sequence. The availability of these genes would allow us to study the functional role of V1a and V1b receptors by disrupting the gene in mice.     

Oxidative damage on DNA induced by asbestos and man-made fibers in vitro

Summary We compared the potential of asbestos and man-made fibers to attack DNA by the determination of the yield of 8-hydroxy-2-deoxyguanosine (8-OH-dGuo) under several in vitro conditions. Asbestos induced 6.6–99.8 of 8-OH-dGuo per 10⁵ dGuo in calf thymus DNA after 20 h of incubation, while the levels of 8-OH-dGuo in man-made fibers were low (3.6–9.4). The amounts of 8-OH-dGuo were strongly stimulated by the addition of H₂O₂ in asbestos, but not in man-made fibers. However, the yield of 8-OH-dGuo was induced more than that with asbestos by the further addition of FeSO₄ in attapulgite, fiberglass, potassium titanate whisker, and metaphosphate polymer. The addition of ethylene diamine tetraacetic acid (EDTA) promoted the induction of 8-OH-dGuo with asbestos and H₂O₂. The effects of mannitol (known as a hydroxy radical scavenger) were not dramatic on 8-OH-dGuo induction by all fibers except fiberglass and basic magnesium sulfate whisker, which induced higher amounts after mannitol addition than in these fibers and H₂O₂. Therefore, it was suggested that asbestos could damage DNA, resulting in 8-OH-dGuo as a cause of point mutation, and also several types of manmade fibers had similar effects to asbestos under certain conditions.     

Molecular defect in siblings with prolidase deficiency and absence or presence of clinical symptoms. A 0.8-kb deletion with breakpoints at the short, direct repeat in the PEPD gene and synthesis of abnormal messenger RNA and inactive polypeptide.

Prolidase deficiency is an autosomal recessive disorder with highly variable symptoms, including mental retardation, skin lesions, and abnormalities of collagenous tissues. In Japanese female siblings with polypeptide negative prolidase deficiency, and with different degrees of severity of skin lesions, we noted an abnormal mRNA with skipping of 192 bp sequence corresponding to exon 14 in lymphoblastoid cells taken from these patients. Transfection and expression analyses using the mutant prolidase cDNA revealed that a mutant protein translated from the abnormal mRNA had an Mr of 49,000 and was enzymatically inactive. A 774-bp deletion, including exon 14 was noted in the prolidase gene. The deletion had termini within short, direct repeats ranging in size of 7 bp (CCACCCT). The "slipped mispairing" mechanism may predominate in the generation of the deletion at this locus. This mutation caused a 192-bp in-frame deletion of prolidase mRNA and was inherited from the consanguineous parents. The same mutation caused a different degree of clinical phenotype of prolidase deficiency in this family, therefore factor(s) not related to the PEPD gene product also contribute to development of the clinical symptoms. Identification of mutations in the PEPD gene from subjects with prolidase deficiency provides further insight into the physiological role and structure-function relationship of this biologically important enzyme.     

Role of cyclin E and p53 expression in progression of early gastric cancer

Background. To elucidate the role that cyclin E overexpression plays in the progression of early gastric cancer, we examined the expression of cyclin E and p53, as abnormal p53 expression is linked with cyclin E overexpression in exerting adverse affects on the cell cycle. Methods. Specimens from 108 early gastric cancers were stained by an immunohistochemical method, using anti-cyclin E and anti-p53 antibodies. Results. The positivity rate of cyclin E expression in early gastric cancer was 33% (36/108). Cyclin E-positive tumors invaded more deeply (P < 0.05), infiltrated lymphatic vessels more frequently (P < 0.01), showed a higher incidence of differentiated cancer (P < 0.01), and more often expressed p53 (P < 0.01) than cyclin E-negative tumors. Differentiated cancers showing coexpression of cyclin E and p53 were more likely to metastasize to the lymph nodes. Conclusions. Overexpression of cyclin E may promote the progression of early gastric cancer. Received for publication on Apr. 27, 1998; accepted on Nov. 17, 1998     

Pronounced synergistic promotion of N-bis(2-hydroxypropyl)nitrosamine-initiated thyroid tumorigenesis in rats treated with excess soybean and iodine-deficient diets.

We have reported that excess soybean treatment and iodine deficiency synergistically interact, resulting in remarkable induction of thyroid hyperplasias in rats. In the present study, modifying effects of excess soybean and iodine-deficient diets were investigated in the post-initiation phase of N-bis(2-hydroxypropyl)nitrosamine [DHPN]-initiated thyroid tumorigenesis in rats. AIN-93G in which casein was replaced with gluten was used as a basal diet to avoid possible iodine contamination. In Experiment 1, F-344 rats of both sexes were sc injected with DHPN at a dose of 2800 mg/kg body weight and then fed a diet containing 0%, 0.8%, 4%, or 20% defatted soybean for 12 weeks, with proportional replacement of gluten by soybean flour. Although no thyroid proliferative lesions were found in any group, the absolute thyroid weights were significantly (p < 0.01) elevated with the 20% soybean treatment. In Experiment 2, after similar sc injection of DHPN, rats were fed a basal diet or a diet containing 20% soybean under iodine normal or deficient conditions for 12 weeks. Soybean feeding to both sexes under iodine deficient but not normal conditions dramatically enhanced the development of thyroid follicular adenomas (p < 0.01) and adenocarcinomas (p < 0.05), in good agreement with decrease in thyroxine and increase in thyroid-stimulating hormone. Thus co-exposure to excess soybean and iodine deficiency results in synergistic promotion of DHPN-initiated thyroid tumorigenesis in rats, of which mechanisms appear to primarily involve effects on serum hormone levels.     

A Novel Characterization Method for Graft‐Polymer Structures Chemically Attached on Thermally Stable Polymer Films

Most polymer grafts in grafted polymer films obtained by radiation‐induced solid graft polymerization are not analyzed in detail due to difficulties in isolation of the grafts without structural decomposition. Herein, a novel structural and molecular weight characterization method is reported for polymer grafts that are chemically attached to thermally and chemically stable polymer substrates, based on a swelling‐induced graft detachment in hot water. Polymer grafts prepared by the radiation‐induced polymerization of alkyl acrylate into poly(ethylene‐co‐tetrafluoroethylene) (ETFE) followed by a sulfonation reaction are found to have a ternary copolymer structure whose monomer units contain –COOH or –SO₃H groups, or both.     

Extraocular sebaceous carcinoma accompanied by invasive squamous cell carcinoma: The first case report and consideration of histogenesis

A 61‐year‐old man presented with a dome‐shaped nodule, 1.2 cm in size, with a central crater covered by keratinous material near the left lateral malleolus. Histological findings demonstrated a basophilic circular cone in the center, surrounded and sharply demarcated by a broad eosinophilic area. The central conical mass was composed mainly of atypical basaloid cells intermingled with scattered atypical sebaceous cells with scalloped nuclei and microvesicular cytoplasms, suggesting sebaceous carcinoma. The peripheral area consisted of atypical keratinizing squamoid cells without sebaceous cells, suggesting invasive squamous cell carcinoma. Atypical sebaceous cells were positive for adipophilin. Atypical basaloid cells were positive for 34βE12 and CAM5.2. Peripheral squamoid cells were positive for 34βB4 and 34βE12 throughout, and were positive for LHP1 in the superficial layer. We herein describe the first case of extraocular sebaceous carcinoma accompanied by invasive squamous cell carcinoma, which might have arisen from biphasic differentiation of cancer stem cells.     

Diet modification and its influence on metabolic and related pathological alterations in the SHR/NDmcr-cp rat,an animal model of the metabolic syndrome

SHR/NDmcr-cp (SHR/NDcp) rats, which carry a nonsense mutation of the leptin receptor gene, are known to spontaneously develop hypertension, obesity and hyperlipidemia, and have therefore found use as an animal model of the metabolic syndrome and type 2 diabetes. However, some recent studies on SHR/NDcp rats revealed only mild elevation of blood glucose levels. To investigate whether metabolic factors including blood glucose and histopathological alterations of SHR/NDcp rats deteriorate with a diabetogenic diet, biochemical and histopathological examinations were conducted with animals fed normal or diabetogenic diets for 20 weeks. SHR/NDcp rats receiving the normal diet displayed obesity, hypertension, hyperlipidemia, and mild elevation of blood glucose and HbA1c levels. Urinary glucose excretion was noted in only 1 out of 6 animals. Histologically, macro- and micro-vesicular steatosis in the liver, glomerular and tubular damages in the kidney and islet hyperplasia mainly of beta cells in the pancreas were characteristically noted. In SHR/NDcp rats fed the diabetogenic diet, obesity was more severe, with higher blood glucose and HbA1c levels, increased numbers of animals with urinary glucose excretion, and more pronounced hepatic steatosis and renal tubular changes. However, elevation of blood glucose levels and urinary glucose excretion proved transient. These observations indicate that the diabetic state and associated histopathological alterations in SHR/NDcp rats are exacerbated by feeding a diabetogenic diet, but the effects are limited. Elevated islet function with compensative insulin secretion might be related to amelioration of the hyperglycemic state. Further diet modification could be needed to induce a more prominent and persistent diabetic state in SHR/NDcp rats.