The enhancing potential of anatoxin a (AFB1) and D-galactosamine (DGA) on development of preneoplastic glutathione S-transferase placental form positive (GST-P+) hepatic foci was examined using an in vivo mid-term assay system based on two-stage concept of hepatocarci-nogenesis. Rats were initially given a single dose (200 mg/kg) of diethylnitrosamine (DEN) intraperi-toneally, and thereafter. with an interval of 2 weeks, AFBl at a graded concentration (0.06, 0.012, 0.0024, 0.00048, and 0.000096 mg/kg i.g.) and DGA (100 mg/kg i.p.) were administered for 6 weeks and then sacrificed. All rats were subjected to a two-thirds partial hepatectomy to induce a potent growth stimulus to DEN-altered hepatocytes at the week 3. The modifying potential was scored by comparing the number and the area (mm2) per cm2 of GST-P+ foci in the liver with those of the corresponding control group given DEN alone. AFBl (at a graded concentration between 96 ng/kg and 60 microgram/kg) exerted a strong promoting effect oil induction of GST-P+ foci with both the number and the area. The logarithmic dose of AFBl and the potency to promote hepatocarcinogenesis were in dose-dependent relationship. DGA, a known necrogenic chemical to cause periportal necrosis and stimulate hepatocellular proliferation. also revealed the increase in the area of GST-P+ foci. although its enhancing potentia1 was 1ess profound than that of AFBl. The results suggest that DGA is also a useful proliferative stimulus m improve the medium-termdetection of unknown carcinogens.
Rats ; Animals

No abstract available.
Forehead*

No abstract available.
Forehead*

This report deals with three cases of accessory hepatic nodules incidentally noted during operation. Two of them were found on the serosal surface of the gallbladder with no connection to the main body of the liver. The other case was in the greater omentum. All three cases were small oval shaped, measuring less than 1 cm in maximum dimension and were composed of histologically normal hepatic tissue and seemed to receive blood supply from the adjacent tissue through the capsular blood vessels. Presence of the fairly well retained intralobular mesenchymal component may reflect that accessory hepatic nodules develop after conjugation of hepatic diverticulum and septum transversum.

The etiologic impacts in primary hepatocellular carcinoma among Koreans seem different from those in other countries with its high incidence and close association of hepatitis B virus infection and liver cirrhosis. A series of 35 lobectomy specimens of hepatocellular carcinoma (HCC) was examined by means of electron microscopy to elucidate the general ultrastructural characteristics and to understand the morphogenesis of various histological growth patterns and cytologic features of HCC. 1) General cytological details of HCC were similar to those of non-neoplastic hepatocytes, but characterized by scantiness of subcellular organelles. Degree of cellular differentiation was not correlated with ultrastructural features of HCC. 2) Acinar pattern of HCC seemed to develop by either dilatation of central bile canaliculus or central cystic degeneration of microtrabecular growth, and clear cell group of HCC was expressed in abundance of glycogen particles and lipid droplets. 3) Intranuclear inclusions of HCC proved to be cytoplasmic herniations of tumor cells, and intracytoplasmic tubular arrays appeared to originate from the endoplasmic reticulum. 4) Hyaline globules seen in HCC corresponded to clumps of microfilamentous structures similar or identical to Mallory's hyalin.
Humans ; Incidence ; Carcinoma, Hepatocellular

No abstract available.
Mandibular Fractures

No abstract available.
Diptera*

Agrobacterium tumefaciens induces cancerous growths called crown galls at wound sites on dicotyledonous plants. A large plasmid called T1 plasmid is responsible for virulence. Upon tumor induction, part of the plasmid, termed T-DNA, becomes integrated into plant genome and its genetic sequences are expressed. These properties allow T1 plasmids to be used as gene vectors in plants. Several in vitro methods for the transfer of T1 plasmid into plant cell have been developed. One of them is the treatment of bacterial spheroplasts and plant protoplasts mixture with polyethylene glycol that is generally used as fusogen in cell-to-cell fusion. Several workers investigated the interaction of bacterial spheroplasts with plant protoplasts in the presence of polyethylene glycol and suggested that the interaction is not fusion but endocytosis. In this report we observed the interaction of Agrobacterium tumefaciens spheroplasts with Nicotiana tabacum protoplasts by electron microscope. Agrobacterium tumefaciens spheroplasts with Nicotiana tabacum protoplasts were prepared and mixed in the presence of polyethylene glycol and high pH-high Ca²⁺ buffer. Then the interaction of the spheroplasts with the protoplasts was examined by transmission electron microscope. After the treatment of polyethylene glycol the spheroplasts adhered to the surface of the protoplasts and then they were engulfed by the protoplasts. After the high pH-high Ca²⁺ buffer treatment the engulfed spheroplasts lost their cell integrity. No fusion process was observed. Thus all these observation suggest that the introduction process of Agrobacterium tumefaciens spheroplasts into Nicotiana tabacum protoplasts with the aid of polyethylene glycol is endocytosis.
Agrobacterium tumefaciens* ; Agrobacterium* ; Endocytosis ; Genome, Plant ; In Vitro Techniques ; Plant Cells ; Plant Tumors ; Plants ; Plasmids ; Polyethylene Glycols ; Protoplasts* ; Spheroplasts* ; Tobacco* ; Virulence ; Wounds and Injuries

No abstract available.
Osteochondroma*

No abstract available.
Mouth* ; Neurilemmoma*