Disparity in perception of the working condition of dental hygienists between dentists and dental hygiene students in Japan.

OBJECTIVES: In Japan, there continues to be a shortage of active dental hygienists. The scope of dental hygienists' practice is also considered to be unclear. One of the reasons for this is that dental hygienists find the working conditions during dental hygiene education different from those in reality. The purpose of this study was to clarify the actual working condition of dental hygienists in dental clinics, as well as evaluate the awareness of dental hygiene students and dentists regarding the working condition of dental hygienists. METHODS: Questionnaires were sent by post to 481 dentists and were distributed to 89 dental hygiene students. The awareness about the working condition of dental hygienists was compared between dentists and dental hygiene students. RESULTS: Two hundred twenty-two dentists and 89 dental hygiene students responded to questionnaires. Dental hygiene students considered the team of 'dental hygienist, dental technician and clerk' to be more effective in providing dental care than dentists (P < 0.001). Among the dentists, 37.1% did not find any clear distinction between hygienists and assistants in their clinics. However, 97.4% of dental hygiene students answered that dental team members should clearly inform patients of the distinction between hygienists and assistants. CONCLUSIONS: This study indicated that there was disparity between dentists' and dental hygiene students' perception of dental hygienists' working conditions, and dental team work was not always effective. For training high quality dental hygienists, all educational institutions related to dentistry must educate students regarding the more realistic dental hygienists' working condition, as well as benefits.

Interstitial-tissue localization of high-molecular-weight kininogen in guinea-pig skin.

A rabbit antibody against the light-chain of guinea-pig high-molecular-weight (HMW) kininogen, which was specific to HWM kininogen and did not recognize low-molecular-weight kininogen, was prepared. This antibody demonstrated the presence of HMW kininogen antigen at the interstitial-tissue space in the guinea-pig skin by means of immunohistochemistry. The interstitial-tissue HMW kininogen antigen was extracted from the skin. This antigen molecule in the skin extract behaved identically as HWM kininogen of plasma in slab-polyacrylamide gel electrophoresis under the presence of sodium dodecyl sulfate followed by immunoblotting. Therefore, it was concluded that HMW kininogen was present in the interstitial-tissue fluid in the skin. The amount of HMW kininogen in the skin extract was quantified by a sandwich enzyme-linked immunosorbent assay with the anti-light-chain antibody and a goat anti-guinea-pig HMW kininogen antibody. On the assumption that the interstitial-tissue volume is 50 ml/100 g wet skin tissue, the average concentration of HMW kininogen in the interstitial-tissue fluid of the skin was calculated to be 23% of the plasma concentration. On the other hand, the proportion of intravascular HMW kininogen (derived from blood remaining in the vessels of the harvested skin) in relation to the total HMW kininogen in the skin extract was quantified by measuring the radio-labelled HMW kininogen which had been injected intravenously as a tracer of the intravascular HMW kininogen. About 5% of the total HMW kininogen in the skin extract was calculated to be derived from the intravascular blood volume of the skin, indicating that the majority of the HMW kininogen in the skin extract was derived from the extravascular-tissue space.

Histochemical demonstration of hydrogen peroxide production by leukocytes in fixed-frozen tissue sections of inflammatory lesions.

The production of H2O2 by cells in cold paraformaldehyde-fixed frozen sections of inflammatory lesions was histochemically demonstrated by incubating them with diaminobenzidine (DAB) for 2 to 6 h. Catalase (150 micrograms/ml, about 1400 U/ml) inhibited the reaction, indicating that H2O2 was required to produce the chromogenic DAB product. Granulocytes (PMNs and eosinophils) were the main types of cells stained by the DAB reaction. Positive staining of macrophages was less frequent. The H2O2 was produced by metabolic enzymes that were still active after cell death and mild fixation. An atmosphere of 95 to 100% oxygen enhanced the specific DAB reaction, and an atmosphere of 100% nitrogen eliminated it. The DAB histochemical reaction to detect H2O2 requires the presence of peroxidases to produce the colored reaction product. Within our tissue sections, such peroxidases were evidently present in excess, because addition of low concentrations of H2O2 significantly increased the reaction product. Although some of the H2O2 produced by the granulocytes may have been derived from the dismutation of superoxide (O2-), the NADPH oxidase pathway for O2- formation did not seem to be involved: NADPH oxidase, a rather labile enzyme, should not be active after mild fixation, and diphenyleneiodonium (100 microM), an inhibitor of flavine-requiring NADPH oxidase, did not inhibit the reaction. Reactive nitrogen intermediates were also not involved, because NG-monomethyl-L-arginine and NG-nitro-L-arginine methyl ester, inhibitors of nitric oxide synthetase, did not appreciably inhibit the reaction. We conclude that stable, non-flavine-requiring oxidases, possibly cyclooxygenases or lipoxygenases, produced the H2O2 measured histochemically by our DAB reaction. These studies were made on tissue sections of acute dermal inflammatory lesions produced in rabbits by the topical application of 1% sulfur mustard [bis(2-chloroethyl) sulfide] in methylene chloride. Both intact PMNs and disintegrating PMNs in the base of the crust produced H2O2. Despite the production of H2O2 and the presence of peroxidase activity, no tissue damage was seen microscopically near the H2O2-producing cells, which indicates that the tissues are well protected by the antioxidants present in this self-limiting inflammatory reaction.

Nonspecific and immune-specific up-regulation of cytokines in rabbit dermal tuberculous (BCG) lesions.

To our knowledge, this is the first sequential study of cytokines in tissue sections of developing and healing tuberculous (BCG) lesions. In situ hybridization, immunohistochemical, and RT-PCR techniques were used. Cytokine mRNAs showed a biphasic pattern. The percentage of mononuclear cells (MN) containing IL-1beta, TNF-alpha, MCP-1, and IL-8 mRNAs was highest in 1- to 3-day lesions, apparently because of the nonspecific inflammatory response caused by the tubercle bacilli in the BCG vaccine. At 5 days, this percentage was significantly reduced. With IFN-gamma, the peak and trough were delayed by 2 days. By 9 days, the percentage of MN containing the mRNAs of all five cytokines had again increased and the rabbits had become tuberculin-positive. In general, MCP-1 and TNF-alpha proteins and the vascular adhesion molecules, ICAM, VCAM, and perhaps ELAM, peaked at about 3 days. Many mononuclear cells surrounding the central areas of solid and liquefied caseous necrosis contained chemokine IL-8 mRNA. IL-8 is known to attract PMN, and PMN were present nearby. In contrast, MN containing chemokine MCP-1 mRNA were present more peripherally in areas rich in macrophages and lymphocytes. The early nonspecific cytokine response seems to be an adjuvant effect of the mycobacteria in BCG vaccine in that it causes a rapid entry of macrophages, lymphocytes, granulocytes, and probably dendritic cells into local sites of antigen deposition. This effect should be considered in developing improved vaccines for the prevention of tuberculosis, because BCG vaccines producing a strong early cytokine response should be more immunogenic than BCG vaccines with similar antigens producing a weak response.

Stage-specific expression of B cell translocation gene 1 in rat testis.

B Cell translocation gene 1 (BTG1) is a member of a new family of putative antiproliferative factors. They are characterized by their rapid, but transient, expression in response to factors that induce growth arrest and subsequent differentiation. In immature rat Sertoli cell cultures, BTG1 messenger RNA (mRNA) increases rapidly after FSH stimulation. We obtained the full-length coding sequence of rat BTG1 complementary DNA for Northern blot analysis and in situ hybridization to determine the temporal expression and spatial distribution of BTG1 mRNA in the rat testis. Northern analysis of isolated adult germ cells and in situ hybridization analysis of adult seminiferous epithelium demonstrated that BTG1 expression was first evident in late primary spermatocytes. The level of BTG1 mRNA was also elevated in secondary spermatocytes, but was maximal in postmeiotic round spermatids where levels were 5 times the background. BTG1 mRNA was not detectable in cells in the M phase of meiosis or spermatids undergoing nuclear elongation and condensation. The oscillation of BTG1 expression from the late prophase of the first meiotic division through spermatozoa release suggests BTG1 involvement in spermatogenesis. High levels of BTG1 mRNA at entry into terminal spermatid differentiation suggests a role consistent with that proposed for the BTG1 family of antiproliferative factors.

Determination of urinary Tamm-Horsfall protein by ELISA using a maleimide method for enzyme-antibody conjugation.

A method for enzyme-antibody conjugation using a new maleimide derivative as coupling reagent has been developed. Since a monomeric conjugate of horseradish peroxidase and Fab' antibody could be readily prepared with high efficiency and reproducibility, the enzyme activity and antigen-binding activity were well preserved and nonspecific staining was greatly reduced. The conjugate is suitable for use in both ELISA procedures and immunohistochemistry. Using both methods we examined the pathophysiological significance of Tamm-Horsfall protein (THP) and the present study describes the ELISA method to quantify urinary THP using the new method with rabbit anti-THP antibody. A low concentration (0.04 M) of urea added to the urine samples increased the linearity of the standard curve and the sensitivity of the assay, permitting the detection of as little as 20 ng/ml THP. Freezing and thawing the urine resulted in variable or lower values of THP concentration. THP concentrations in urine as determined by ELISA were stable for at least one month after -70 degrees C storage, but not after -30 degrees C storage. There was no correlation between THP concentrations in 24 h urine samples and the morning urine of the same patient. These results suggest that it is essential to use fresh or -70 degrees C stored 24 h urine samples with added urea (0.04 M) for the determination of THP concentrations in urine by the present enzyme-antibody conjugation method. The THP concentration in normal 24 h urine of young children was found to be less than 51.8 mg/g Cr.

Application of a new method of antibody-enzyme conjugation with maleimide derivative for immunohistochemistry: hepatocellular production, interstitial tissue distribution, and renal cell reabsorption of plasma albumin in guinea pig.

A new sophisticated method for enzyme-antibody conjugation developed in quantitative solid-phase enzyme immunoassay was revealed to be an applicable method for immunohistochemistry; one that offered several advantages over present methods. Using a new maleimide derivative as a coupling reagent, monomeric conjugate of horseradish peroxidase and Fab' antibody was easily prepared with high efficiency and reproducibility. Nonspecific staining was greatly reduced in the presence of this monomeric conjugate. Since the enzyme activity and antigen-binding activity were well preserved in the conjugate, the reaction was strong enough to analyze the antigen localization in intracellular organelles or in interstitial tissue space by both light and electron microscopy. The fate of plasma albumin was investigated in liver, skin, and kidney using the new method with rabbit anti-guinea pig albumin antibody, and satisfactory results were obtained. In the liver, the reaction products were observed in the rough and smooth endoplasmic reticulum and the Golgi apparatus in hepatocytes, which confirmed the synthesis of plasma albumin in hepatocytes of guinea pig. In a study of the distribution of albumin, reaction products were seen in the intercellular space of the epidermis, along the basement membranes of epidermis and of proximal convoluted tubules in kidney, and among the collagen fibers in interstitial tissue, particularly at papillary dermis, suggesting the wide distribution of plasma albumin in interstitial extravascular tissue spaces. In addition, positive reaction was obtained in the apical vesicles and the lysosomes of the proximal convoluted tubules and in the pinocytotic vesicles of the basal cells of epidermis, suggesting the reabsorption and destruction of albumin in the kidney and the skin.

Novel subtyping of intestinal metaplasia in the human stomach: brain-type glycogen phosphorylase expression in the proliferative zone and its relationship with carcinogenesis.

Although reports have suggested the incomplete type of intestinal metaplasia (IM) had a close correlation with carcinoma, considerable data showed no apparent relationship between the particular type of IM and the intestinal type carcinoma. The purpose of this study was to establish a novel classification of IM using brain-type glycogen phosphorylase (BGP) from a carcinogenetic viewpoint. The only isoform expressed in gastric cancer was BGP using polymerase chain reaction analysis. We studied 136 specimens with gastric carcinoma and the adjacent IM using specific anti-BGP antibody with its correlation to subtypes of IM, proliferating cell nuclear antigen-labeling index, and various oncogene products. Brain-type glycogen phosphorylase was expressed in 80.5% of the intestinal type and 18.8% of the diffuse type of carcinoma and in 87.5% and 41.6% in the generative zone of IM adjacent to cancer foci, respectively, whereas no reactivity was observed in the normal gastric mucosa. The proportion of the positivity in the cancer and IM was significantly greater in the intestinal-type carcinoma than in the diffuse type. The expression of BGP in the generative cells of IM had no significant correlation with the conventional type of IM. Intestinal metaplasias with BGP expression were significantly higher in a proliferating state than in those without BGP, and some of them that were coexpressed accumulated p53 in the generative cells. The relationship between IM with BGP in the generative cells and intestinal-type carcinoma was apparently closer than the conventional subtype of IM and gastric cancer. Intestinal-type carcinoma might arise from some of these proliferating cells with BGP.

Capacity for epithelial differentiation in synovial sarcoma: analysis of a new human cell line.

AIM: To analyse the capacity for epithelial differentiation in synovial sarcoma using a new human cell line. METHODS: A new human cell line, KU-SS-1, was established from a monophasic, spindle cell type of synovial sarcoma by grafting those cells on to severe combined immunodeficient (SCID) mice and then transferring them to in vitro culture systems. The KU-SS-1 cells were characterised by light and electron microscopy, and by immunohistochemical, flow cytometric, and cytogenetic analysis. RESULTS: Primary tumour and cultured cells at passage 20 showed a positive reaction for vimentin, which is a mesenchymal marker. After 40 passages, subcultured cells were injected into SCID mice to induce further tumours. These advanced subcultured cells and the tumour cells that they induced were positive for cytokeratin, an epithelial marker, and exhibited epithelial ultrastructural features such as intermediate junctions. Furthermore, two colour immunofluorescent analysis for proliferating nuclear cell antigen (PCNA) and intermediate filaments showed that a large number of PCNA expressing cells were positive for vimentin, and that part of this fraction also expressed cytokeratin. The existence of cells with reactivity for these three markers indicated that, in this cell line, a fraction with high proliferating capacity had both mesenchymal and epithelial markers. In addition, cytogenetically, this cell line expressed the SYT-SSX chimaeric transcript as a result of the t(X;18) (p11;q11) translocation. CONCLUSIONS: A human synovial sarcoma cell line was established and stably maintained in cell culture for more than 70 passages. In addition, this cell line showed epithelial differentiation, which supports the hypothesis that synovial sarcoma is a carcinosarcoma like tumour with true epithelial differentiation. This cell line will be a useful tool for investigating the nature of this tumour and will contribute to clinical studies.

Blood Transfusion Induced Opportunistic Adult T Cell Leukaemia/Lymphoma after Hodgkin's Disease.

A patient previously treated for Hodgkin's disease (HD) developed secondary adult T cell leukaemia/lymphoma (ATL) after blood transfusion. Immunohistochemical analysis and polymerase chain reaction support the diagnosis. To the best of our knowledge this is the first occurrence of transfusion induced ATL occurring as a second malignancy after treatment for HD. The leukaemia/lymphoma probably developed on the basis of underlying immunosuppression.

Direct evidence for systemic fibrinogenolysis in a patient with metastatic prostatic cancer.

Although the possible occurrence of systemic fibrinogenolysis has been suggested in patients with metastasising prostatic cancer (MPC), direct evidence is lacking. We report on a patient with MPC whose laboratory data were consistent with hyperfibrinolysis: marked decrease of alpha 2-antiplasmin (AP) level (less than 50% of normal), increase of plasmin-alpha 2-antiplasmin complex, D-fragment of fibrin and fibrinogen degradation products [FDP(D)] and cross-linked fibrin degradation products (XDP). The patient neither showed laboratory nor clinical evidence for consumption coagulopathy except for a slight increase in thrombin-antithrombin III complex level. Immunoblotting of the patient's serum using an anti-fibrinogen antibody revealed the presence of a 250 kDa protein in addition to DD fragments. Following reduction of this protein by 2-mercaptoethanol after extraction from SDS-PAGE gel, gamma-chain of fibrinogen (47 kDa) was found by immunoblotting using a monoclonal antibody recognising a 86-302 residue of the gamma-remnant of fibrinogen. Moreover, the 250 kDa protein did not bind to Sepharose 4B to which a monoclonal antibody recognising the N-terminus of fragment D was conjugated. These findings indicated that this protein was not fragment DY, but rather fibrinogen fragment X. With the retraction of the prostatic tumour by an effective therapy, the patient's AP level increased gradually. When the plasma AP level rose to 60% of normal, the fragment X was no longer detectable. These findings suggested that systemic fibrinogenolysis occurred in the patient with MPC only when AP levels were markedly decreased.

A case of ductal adenoma of the breast which contains high-concentration of steroid-hormone receptors.

A case of ductal adenoma of the breast in a 64-year-old Japanese woman is reported. The patient presented with a well-defined, 0.9 cm, firm mass in the right breast. Histological examination of the excised tumor revealed small and medium-sized ductules forming a nodular pattern partly surrounded by a thin layer of mature collagenous fibers. A few hyalinized fibers were also observed among the ductules, which had a clearly defined basement membrane, diagnosed as ductal adenoma of the breast. Determination of steroid hormone receptor by a dextran-coated charcoal method revealed that the ductal adenoma contained high concentration of estrogen receptor (ER) and progesterone receptor (PgR) (280 and 105 fmol/mg protein, respectively). The patient had a previous history of invasive ductal carcinoma of the left breast and had undergone a modified radical mastectomy 4 years earlier. The contralateral breast cancer was also positive for both ER and PgR (350 and 78 fmol/mg protein, respectively).

The cytokines NAP-1 (IL-8), MCP-1, IL-1 beta, and GRO in rabbit inflammatory skin lesions produced by the chemical irritant sulfur mustard.

Developing and healing dermal inflammatory lesions were produced in rabbits by the topical application of dilute sulfur mustard (SM), the military vesicant. In tissue sections of such lesions, cells containing the mRNA of important cytokines were identified with in situ hybridization techniques. These cytokines were neutrophil attractant/activation protein-1 (NAP-1 (also called IL-8), monocyte chemoattractant (activating) protein 1 (MCP-1), interleukin 1 (beta) (IL-1 (beta)), and GRO (a growth factor and chemokine). Mononuclear cells (mainly macrophages and activated fibroblasts) contained the mRNA of all four of these cytokines. A higher percentage of cytokine-producing mononuclear cells (macrophages and activated fibroblasts) was present in lesions at 2 days (their peak size) than at 6 days, when they were almost healed. Granulocytes emigrated from the bloodstream, passed through the lesions, and were the major constituent of the protective crust. This sequence correlated with the distribution of cells able to produce NAP-1: At 2 days and 6 days, the mononuclears that contained messenger RNA for this granulocyte chemoattractant were found mainly in the upper part of the dermis. At 2 days and 6 days, cells containing the mRNA of IL-1, a primary cytokine, were also found predominantly in the upper dermis, i.e., nearest the site of injury. In contrast, mononuclears containing the mRNA of MCP-1 (a monocyte chemoattractant), and the mRNA of GRO (a granulocyte chemoattractant) were more equally distributed throughout the dermis. SM stimulated hair follicle epithelial cells to up-regulate GRO mRNA and, to a lesser degree, NAP-1 mRNA. Apparently, the irritation produced by SM directly or indirectly induces such epithelial cells to manufacture these growth factors. In the rabbit, hair follicles are known to be the main source of new epithelial cells after the covering epithelium has been destroyed. Therefore, GRO is probably a major autocrine-paracrine stimulus for such repair. A brief review of the role of cytokines in dermal inflammation is presented.

Immunohistochemical studies on synthesis and distribution of Hageman factor and kininogen.

Immunohistochemical localization of Hageman factor and high molecular weight kininogen were investigated in liver, skin and kidney of guinea pig using a new conjugation method with maleimide derivative as the coupling reagent at the level of light and electron microscopes. In the liver, the positive reactions of both factors were observed in the rough and smooth endoplasmic reticulums and the Golgi apparatus in hepatocytes. In Kupffer cells and sinusoidal endothelial cells, the reaction products were visible only in the endocytotic vesicles. These findings suggested that guinea pig Hageman factor and high molecular weight kininogen were synthesized only in hepatocytes at least the liver. In the skin, positive reactions were seen in the intercellular space of epidermis, and along the basement membranes of epidermis and vessels, and among the collagen fibers in interstitial tissue particularly in papillary dermis. This interstitial presence of these molecules was also seen in liver and kidney, which suggested that Hageman factor and high molecular weight kininogen were widely distributed in the interstitial tissue space even under normal conditions. In addition, positive reactions were obtained in the reabsorption vesicles and the lysosomes of the proximal convoluted tubules of kidney and in the pinocytotic vesicles of the basal cells of epidermis. According to these findings, it was suggested that both factors were produced in hepatocytes, secreted into the blood stream, distributed in the interstitial tissue by vascular permeability even under normal condition, and reabsorbed and catabolized in the kidney and the skin.

Hageman factor dependent pathway in local vascular permeability enhancement.

The possibility of an involvement of the kallikrein-kinin system in increasing vascular permeability induced by intradermal injection of the guinea pig activated Hageman factor (beta HFa) was examined. In vitro system, the kinin generation was observed in guinea pig plasma when the plasma was incubated with beta HFa. This kinin generation was dependent upon the dose of beta HFa added and upon the presence of plasma prekallikrein, since 97 percent of the kinin release was diminished by removing the prekallikrein in plasma by treatment with anti-prekallikrein antibody. These results suggested that the Hageman factor-kallikrein-kinin cascade in guinea pig was similar to those in human and bovine plasma. In the permeability experiment in vivo, a simultaneous injection of soybean trypsin inhibitor (10(-6) M), which is the inhibitor of guinea pig plasma kallikrein, inhibited the permeability response to beta HFa by more than 90 percent. The permeability response to beta HFa was attenuated 5 fold in animals depleted of the circulating plasma prekallikrein by intraarterial antibody administration. These results indicated the participation of plasma prekallikrein in the permeability reaction to beta HFa. A simultaneous injection of a kinin destructive enzyme, carboxypeptidase B, diminished the permeability reaction to beta HFa, without any inhibition of the amidolytic activity of beta HFa or plasma kallikrein. A simultaneous injection of an inhibitor of a kinin destructive enzyme (kininase II), SQ 20,881(Glu-Tyr-Pro-Arg-Pro-Gln-Ile-Pro-Pro-OH), augmented the permeability reaction to beta HFa 10 fold, without any effect on the amidolytic activity of beta HFa or plasma kallikrein.(ABSTRACT TRUNCATED AT 250 WORDS)

Cancer prevention by natural carotenoids.

Various natural carotenoids were proven to have anticarcinogenic activity. Epidemiological investigations have shown that cancer risk is inversely related to the consumption of green and yellow vegetables and fruits. Since beta-carotene is present in abundance in these vegetables and fruits, it has been investigated extensively as possible cancer preventive agent. However, various carotenoids which co-exist with beta-carotene in vegetables and fruits also have anti-carcinogenic activity. And some of them, such as alpha-carotene, showed higher potency than beta-carotene to suppress experimental carcinogenesis. Thus, we have carried out more extensive studies on cancer preventive activities of natural carotenoids in foods; i.e., lutein, lycopene, zeaxanthin and beta-cryptoxanthin. Analysis of the action mechanism of these natural carotenoids is now in progress, and some interesting results have already obtained; for example, beta-cryptoxanthin was suggested to stimulate the expression of RB gene, an anti-oncogene, and p73 gene, which is known as one of the p53-related genes. Based on these results, multi-carotenoids (mixture of natural carotenoids) seems to be of interest to evaluate its usefulness for practice in human cancer prevention.

Cell proliferation in N-nitrosodiethylamine (DEN)-treated rat liver parenchyma correlated with tumor development.

BACKGROUND/AIMS: The authors wanted to clarify the relationship between the cell proliferation of the liver parenchyma and the development of hepatocellular carcinoma. MATERIALS AND METHODS: Liver specimens of 22 N-nitrosodiethylamine-treated rats and 15 normal control rats were examined using laparotomic biopsies at 30 day intervals, followed by total liver resections after sacrifice. Magnetic resonance imaging was performed to evaluate the development of hepatocellular carcinoma at each period before biopsy. Cell proliferation was determined using the thymidine analogue, bromodeoxyuridine, which is taken up by S-phase cells during DNA synthesis. RESULTS: The cell proliferation of the liver parenchyma gradually increased by the 60th day after the initiation of nitrosodiethylamine administration. The labeling index on the 60th day was 0.33 +/- 0.10%. No abnormal mass lesions were identified in either the control rats or the nitrosodiethylamine-treated-rats within this period. By the 90th day in the nitrosodiethylamine-treated-rats, the labeling index of non-cancerous portion had rapidly increased by as much as 1.60 +/- 0.38%, and magnetic resonance imaging demonstrated small high signal intensity nodules on T1-weighted images. They were either hyperplastic nodules or well-differentiated hepato-cellular carcinomas. Moderately or poorly differentiated hepatocellular carcinomas developed at the 120th day. CONCLUSIONS: The cell proliferation of non-cancerous portion of nitrosodiethylamine-treated-rats livers increased immediately before the development of hepatocellular carcinomas. Detection of this rapid increase of cell proliferation in non-cancerous portions of the liver may suggest a high probability of development of hepatocellular carcinoma in the near future.

MR imaging of lingual carcinoma: comparison with surgical staging.

The purpose of this study was to determine the usefulness of magnetic resonance (MR) imaging for the preoperative staging of 18 patients with lingual carcinomas. Tumor stage as determined by MR imaging was compared with pathological stage. Conspicuity of tumors was compared among dynamic MR, T2-weighted, and postcontrast T1-weighted images. The tumor stage was evaluated correctly with MR imaging in 15/18 patients (83.3%). One patient was overstaged and two understaged due to incorrect diagnosis of size. In all T4 cases, tumor extension was diagnosed correctly. Dynamic MR and T2-weighted images were superior to postcontrast T1-weighted images in delineating and showing the extension of carcinomas. However, dynamic MR imaging showed no significant superiority to T2-weighted imaging. We conclude that MR imaging is of great value in the staging of lingual carcinoma. Dynamic study should be performed only when the lesion is undetectable or equivocal on T2-weighted imaging.

Small cell carcinoma of the stomach: a case report.

A case of a gastric small cell carcinoma discovered incidentally by screening ultrasonography is presented. Ultrasonography demonstrated a subcardial metastatic lymph node and multiple hepatic metastatic lesions. Upper GI series and gastroendoscopy revealed a large ulcerated tumor in the cardia of the stomach, and a Borrmann type II tumor, 4 x 2.5 cm, was found in the resected stomach. We describe the radiological findings of the upper GI series, ultrasonography, CT, and gastroendoscopy, and review the literature.

[Remodeling of basement membrane in association with cancer invasion].

Type IV collagen the major component of basement membrane (BM), is composed of six genetically distinct alpha chains. In normal breast tissue, benign breast tumors, and in the intraductal components of invasive ductal carcinoma, alpha 1 (IV) and alpha 2 (IV) chains were stained in all BM, whereas alpha 5 (IV) and alpha 6 (IV) chains were restrictively localized in a linear pattern in the epithelial BM. However, in invasive ductal carcinoma, alpha 1 (IV) and alpha 2 (IV) chains were discontinuously or negatively stained in the cancer cell nest, and the assembly of alpha 5 (IV) and alpha 6 (IV) chains into the BM was completely inhibited. The results indicate that the mammary gland forms a second network of BM composed of alpha 5 (IV)/alpha 6 (IV) chains, in addition to the classic network of alpha 1 (IV)/alpha 2 (IV) chains. Remodeling of type IV collagen alpha chains during the development of invasive breast cancer seems to be differentially regulated, and to be associated with modification of histopathological findings.