Accumulated photon echoes by using a nonlaser light source

Accumulated photon echoes have been observed by use of a light-emitting diode. This is to our knowledge the first observation of photon echoes that are excited by a nonlaser light source. In the incoherent-light photon echo, the time resolution is equal to the inverse of the overall spectral width of the excitation light. Therefore we can easily get a high time resolution by using nonlaser light with a broad spectrum. Moreover the use of nonlaser light in the photon-echo experiment will extend the technique into wavelength regions where lasers are not currently available.

[Magnetic resonance imaging in chronic toluene abuse, and volitional hyperkinesia]

We described the central nervous system impairments and findings of magnetic resonance imaging (MRI) of the brain in three chronic toluene abusers. Patient 1 and 2 had a history of chronic toluene inhalation for 1 or 2 years and patient 3 has a history of it for 16 years. The patients were evaluated after an abstinence period of at least 4 weeks, to avoid neurologic effects of acute intoxication. Neurologic signs included cerebellar, cognitive and pyramidal dysfunctions in all 3 patients and hyperkinésie volitionnelle (HV; volitional hyperkinesia) in patient 3 who had a long history of toluene inhalation. This HV was found to be tremulous by surface electromyography. Appearance of HV in chronic toluene abuse seems to be related to a period or quantity of inhalation of toluene. T2-weighted MRI in the 3 patients revealed the following abnormalities: (1) increased signal intensity of middle cerebellar peduncle and cerebellar white matter, deep cerebral white matter, and posterior limb of internal capsule; and (2) decreased signal intensity of thalamus and basal ganglia. Proton-weighted MRI in patient 3 with HV showed decreased signal intensity of lateral portion of the thalamus and tegmentum of the brainstem. These MRI findings correlate remarkably well with the neurologic signs seen in the 3 patients. Cerebellar, cognitive, and pyramidal dysfunctions appear to be related to involvement of middle cerebellar peduncle (cerebellar white matter), deep cerebral white matter, and internal capsule, respectively, and HV seems to correlate with involvement of the thalamus or tegmentum of the brainstem, especially the latter.

Conceptual history of the nigrostriatal dopamine system

The history of the nigrostriatal dopamine system may provide a prime example of the two faces of scientific development. First, a given concept is replaced by another simply as a result of methodologies being improved, and second, successive technical improvements make seemingly settled controversies even more complicated and disputable. The nigrostriatal pathway, which had been unrecognizable with Nauta's silver impregnation method, became apparent by use of the more sensitive silver impregnation method of Fink-Heimer. The sensitivity of the latter method, however, was still insufficient to reveal the whole extent of another ascending dopamine system, the mesocortical dopamine system, until its existence was established through the application of glyoxylic acid fluorescent histochemistry. Electron microscopic analysis of nigrostriatal dopamine synapses in properly fixed tissue was initiated by the demonstration of dark type terminal degeneration, which was induced by either electrolytic lesions or chemical destruction with a specific toxin (6-hydroxydopamine) of the substantia nigra and medial forebrain bundle. The degenerating terminal boutons, thus produced, invariably formed postsynaptic membrane specializations of asymmetric type. However, the asymmetric nature of the synaptic morphology, although later confirmed by the combined study of chemical lesions and autoradiographic anterograde tracing, was seriously challenged with the introduction of electron microscopic immunohistochemistry. The latter method has consistently revealed that symmetric en passant synapses or axonal varicosities with no synaptic membrane specializations are the only tissue compartments immunoreactive to antibodies against dopamine and its synthetic enzyme tyrosine hydroxylase. In view of the fact that more than 95% of the nigrostriatal projection neurons are dopaminergic, it is difficult to satisfactorily interpret all the available and seemingly paradoxical fine structural data. In this context, a novel concept has emerged in the process of eliminating all the possible alternative interpretations. The concept is that single nigrostriatal neurons form two chemically distinct types of synapses, one dopaminergic symmetric en passant bouton and another non-dopaminergic (still chemically unclassified) asymmetric terminal bouton. If the concept is a valid one, it contradicts Dale's long standing principle, as defined by Eccles: at all the axonal branches of a neuron there is liberation of the same transmitter substance or substances. Furthermore, a certain population of substantia nigra pars reticulata neurons has recently been recognized to be immunoreactive to both dopamine synthetic tyrosine hydroxylase and GABA synthetic glutamate decarboxylase. These single neurons send projections to both the striatum and superior colliculus by way of axon collaterals.(ABSTRACT TRUNCATED AT 400 WORDS)

Characterization of cytokine LD78 gene promoters: positive and negative transcriptional factors bind to a negative regulatory element common to LD78, interleukin-3, and granulocyte-macrophage colony-stimulating factor gene promoters

Cytokine LD78 is a human counterpart of the mouse macrophage inflammatory protein 1 alpha/hematopoietic stem cell inhibitor. Promoters of the LD78 alpha and LD78 beta genes showed similar inducible activities in two leukemic cell lines, K562 and Jurkat, but the induction mechanisms differed between the two cell lines. Further characterization of the LD78 alpha promoter indicated that multiple positive and negative regulatory elements are present, some of which are differentially required for induction and repression of the promoter activity in different cells. One of the negative regulatory elements, ICK-1, functioned in both cell lines in the absence and presence of stimulation and was shown to be a recognition site for positive and negative transcriptional factors. This ICK-1 element contained a direct repeat, and similar repeats were also found in the negative regulatory elements of hematopoietic growth factor interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) gene promoters. Nuclear extracts from K562 and Jurkat cells formed several protein-DNA complexes with the LD78 alpha ICK-1 element, one of which was also observed with the IL-3 and GM-CSF ICK-1 elements. Results from in vivo and in vitro analyses suggested that the protein forming this complex functions as a negative factor. The binding affinity of this protein, ICK-1A, to the LD78 alpha ICK-1 element was low and was significantly affected by the incubation temperature and the salt concentration in the binding buffer. ICK-1B, another protein bound specifically by the LD78 alpha ICK-1 element, was shown to be a positive factor important for induction of the promoter. These results suggested that ICK-1A plays an important role in balanced expression of LD78, IL-3, and GM-CSF during hematopoietic cell growth and differentiation.

A standardized method of using nude mice for the in vivo screening of antitumor drugs for human tumors

Human tumors transplanted into nude mice have long been used to assess the effectiveness of antitumor drugs and yet there is still no established standard method in preclinical practice for screening new antitumor drugs in vivo using nude mice. Thus, a cooperative study on the feasibility of a human tumor/nude mouse system for the in vivo screening of drugs was conducted by the Japanese Research Society for Chemosensitivity of Cancer. Two human stomach cancers, H-111 and SC-6-JCK, and one human colon cancer, Co-4, were transplanted serially into nude mice and used as gastrointestinal tract tumors with stable tumor growth. The appropriate dosage of six well-known antitumor drugs [mitomycin C (MMC), cyclophosphamide (CPA), nimustine hydrochloride 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), cis-platinum (II) diaminodichloride (CDDP), adriamycin (ADM) and 5-fluorouracil (5-FU)] in human tumor-bearing nude mice was determined based on the maximum tolerance dose of the drug. The respective dosages were 6 mg/kg of MMC x 1 (i.p.), 120 mg/kg of CPA x 1 (i.p.), 30 mg/kg of ACNU x 1 (i.p.), 8 mg/kg of CDDP x 1 (i.p.), 8 mg/kg of ADM x 1 (i.v.), and 50 mg/kg of 5-FU q4d x 3 (i.p.). Three weeks after treatment, drug effectiveness was judged by the tumor growth inhibition rate. Treatment with these appropriate doses appeared to show the maximum effect of the respective drugs on the tumor-bearing nude mice.(ABSTRACT TRUNCATED AT 250 WORDS)

Applications of biotinylated V3 loop peptides of human immunodeficiency virus type 1 to flow cytometric analyses and affinity chromatographic techniques

A principal neutralizing determinant of human immunodeficiency virus type 1 (HIV-1) lies within the V3 loop of gp120, the external major envelope glycoprotein. V3 loop peptides derived from two HIV-1 strains, HTLV-III BH-10 (V3-BH10) and LAVELI (V3-ELI), were synthesized and biotinylated. The binding of both biotinylated V3-BH10 and V3-ELI to the surfaces of MOLT-4 clone 8 cells was demonstrated by flow cytometric analyses. Both the peptides (more than 2 microM) bound to the cells (2 x 10(5) in a dose-dependent manner. The binding of biotinylated V3-BH10 was specifically inhibited by a neutralizing monoclonal antibody (0.5 beta). The binding of both of the biotinylated V3 loop peptides was enhanced by the addition of unlabeled V3-BH10. In addition, the peptides were employed as ligands on affinity columns. A major V3 loop binding protein (V3BP) was purified from the membrane soluble fraction of MOLT-4 cells by successive application to two different V3 loop columns. V3BP consisted of two major polypeptides (32 and 33 kDa). The SDS-PAGE profile of V3BP did not change under non-reducing conditions, but only a single band was observed after analysis on native PAGE. The major peak of the eluate as determined by size exclusion chromatography was broad and the estimated relative molecular mass was much larger than 33 kDa, suggesting that V3BP comprises several subunits. Taken together, we confirmed that the V3 loop peptides are useful in the characterization of V3BP(s) of which they are conformational ligands.

[Characterization of primary and metastatic cell lines established from a patient with renal cell carcinoma]

We established four renal cell carcinoma (RCC) cell lines (HANKS), namely the primary tumor (HANKS-Pr), metastasized to the lung (HANKS-Lu), liver (HANKS-Li) and lymph node (HANKS-LN) derived from a patient with advanced RCC, and analyzed their characters. Each had an epithelial morphology and exhibited multilayering. These cell lines have been maintained for more than 36 months and over 100 in vitro passages. In karyotype analysis, the common aberration in the four cell lines was marker chromosome t (3;18) (p13;q21). In soft agar culture, HANKS-Pr showed the lowest growth. Furthermore, we found high level expression of major histocompatibility complex (MHC) class I antigen on HANKS-Pr and HANKS-Lu, and low expression of MHC class II antigen on four cell lines. HANKS-LN had transplantability in nude mice. We determined the different biological properties among HANKS cell lines stemming from the same origin.

Progression of signet ring cell carcinomas in the human stomach

BACKGROUND

Stomach cancers show various growth patterns. It remains to be clarified how this variability is related to the genetic changes that occur during tumor progression.

METHODS

To estimate the genetic changes from tumor ploidy, maps were made (using DNA cytofluorometry of metaphase cells in histologic sections) of 39 advanced signet ring cell carcinomas of the human stomach and correlated with tumor stage and the size of the primary mucosal lesion.

RESULTS

Aneuploid area and multipattern aneuploidy were particularly common in advanced cancers with primary mucosal lesions smaller than 2 cm in diameter, of which a large portion were predominantly aneuploid and already diffusely infiltrating. As the tumor stage advanced, the incidence of aneuploidy in the mucosal lesion increased, whereas predominantly aneuploid tumors were less common as primary mucosal lesions became larger. Purely diploid areas with an incidence of polyploidy as low as in early cancers were common in advanced cancers. In addition, there were diploid-appearing cancer cells that infiltrated diffusely and were accompanied by polyploid as often as aneuploid cells. Some of these were aneuploid at the chromosomal level.

CONCLUSIONS

In signet ring cell carcinoma, aneuploid cells show higher invasive activity toward the extramucosal part and may occur incidentally in originally diploid tumors, depending on the degree of genetic instability. An analysis of polyploidy is useful for differentiating cytometrically diploid (but actually, aneuploid) cells from diploid cells with minor genetic abnormalities.

[A study of changes in distribution pattern of proliferating cells associated with progression of human colorectal benign and malignant tumor using PCNA immunohistochemistry]

We studied cell kinetics of colo-rectal neoplasms using PCNA (the auxiliary protein of DNA polymerase-delta) immunohistochemistry. We analyzed the distribution pattern of PCNA positive cells on normal colon mucosa, adenoma (6 cases) and cancer (early: 33 cases, advanced: 6 cases). PCNA positive index (PI) was calculated as the percentage of PCNA positive tumor cells in relation to the total number (about 1000) of the tumor cells. PCNA positive indices were 30% in normal colon mucosa, 49% in adenoma and 72% in cancer, respectively. There were statistically significant differences between three mean values (p < 0.01). In normal colon mucosa PCNA positive cells are localized at the lower part of mucosa, but, in adenoma, they are found at the more upper part of mucosa too. In cancer, PCNA positive cells were localized diffusely and their immunoreactivity is higher than those of the normal mucosa and adenoma. In conclusion, our results suggests that the ratio of PCNA positive cells almost equivalents to growth fraction, and is correlated with the histological grading of colo-rectal tumor, but not correlated with depth of carcinoma. It is presumed that carcinoma has a higher ratio of PCNA positive cells than adenoma, and therefore carcinoma has higher proliferating cell density than adenoma.

[Embolization of the internal maxillary artery for severe epistaxis--including an experience of the approach from the superficial temporal artery]

Six cases of severe epistaxis were treated with the super-selective intraarterial embolization of the internal maxillary artery. Tens of fragments of Gelfoam were delivered into the distal internal maxillary artery and, additionally, embolized by several pieces of the coils. In a case with cerebral infraction, catheter was inserted via the superficial temporal artery. There were no complications due to these procedures in all cases of this study. It is considered that therapeutic intraarterial embolization of the internal maxillary artery is an effective therapy for severe epistaxis and the superficial temporal artery approach is useful for selected cases.

[MR tractography--visualization of structure of nerve fiber system from diffusion weighted images with maximum intensity projection method]

We developed a new noninvasive technique to visualize the anatomical structure of the nerve fiber system in vivo, and named this technique magnetic resonance (MR) tractography and the acquired image an MR tractogram. MR tractography has two steps. One is to obtain diffusion-weighted images sensitized along axes appropriate for depicting the intended nerve fibers with anisotropic water diffusion MR imaging. The other is to extract the anatomical structure of the nerve fiber system from a series of diffusion-weighted images by the maximum intensity projection method. To examine the clinical usefulness of the proposed technique, many contiguous, thin (3 mm) coronal two-dimensional sections of the brain were acquired sequentially in normal volunteers and selected patients with paralyses, on a 1.5 Tesla MR system (Signa, GE) with an ECG-gated Stejskal-Tanner pulse sequence. The structure of the nerve fiber system of normal volunteers was almost the same as the anatomy. The tractograms of patients with paralyses clearly showed the degeneration of nerve fibers and were correlated with clinical symptoms. MR tractography showed great promise for the study of neuroanatomy and neuroradiology.

Double-negative (CD4- CD8-) T cells from adult T-cell leukemia patients also have poor expression of the T-cell receptor alpha beta/CD3 complex

We present four patients with adult T-cell leukemia (ATL) derived from a novel T-cell subset (CD4-, CD8- [double-negative, DN], T-cell receptor [TCR] alpha beta+). In the ATL cells of these patients, neither gene nor surface expression of CD4 and CD8 antigens was detected. Clinical and laboratory data showed no difference between DN-ATL and CD4+ATL patients. In contrast to typical CD4+ATL cells, DN-ATL cells were shown to express the protein and messenger RNA (mRNA) for S100 beta in immunocytochemical assay and the reverse-transcription polymerase chain reaction assay. The mean fluorescence intensity of the TCR/CD3 complex was extremely low in all four DN-ATL patients as well as in typical CD4+ ATL. All four patients had TCR beta and gamma chain gene rearrangements, with deletion of TCR delta chain gene and mRNA expression for TCR alpha, beta, and CD3 delta but not for TCR gamma and delta chain genes. Thus, CD4- CD8- TCR alpha beta T cells are also a target for human T-cell lymphotrophic virus type I-induced leukemogenesis. In addition, expression of the TCR alpha beta/CD3 complex on the DN-ATL cells was further diminished by the addition of anti-CD3 or anti-TCR alpha beta monoclonal antibody. These results suggest that the decreased expression of the TCR alpha beta/CD3 complex by ATL cells plays a key role in the development of ATL, irrespective of CD4 expression.

Tyrosine hydroxylase immunoreactivity in cerebellar Purkinje cells of the rat

Employing tyrosine hydroxylase (TH) immunohistochemistry, we have revealed that TH immunoreactivity occurs in cerebellar Purkinje cells in the rat. These TH-immunoreactive Purkinje cells were distributed predominantly in the crus I & II ansiform lobules and the paraflocculus, and to a lesser extent in the I & X vermal lobules. Since Purkinje cells in such cerebellar regions displayed no immunoreactivity to dopamine-beta-hydroxylase, the TH-immunoreactive Purkinje cells identified in the present study might contain dopamine or L-DOPA.

MPTP neurotoxicity to cerebellar Purkinje cells in mice

The pyridine derivative 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is recognized as a crucial neurotoxin which destroys nigrostriatal dopamine cells, thereby inducing neurological signs relevant to idiopathic Parkinson's disease. In the present study, we have revealed MPTP neurotoxicity to cerebellar Purkinje cells in mice. Systemic MPTP injections to mice resulted in a substantial loss of Purkinje cells in a dose-dependent fashion. The MPTP-induced Purkinje cell loss occurred markedly in the crus I and II ansiform lobules and the paraflocculus. Such a neurotoxic effect was largely prevented by the monoamine oxidase B inhibitors pargyline and deprenyl, and the dopamine uptake inhibitors mazindol and benztropine.

Expression of sialyl-Tn antigen is correlated with survival time of patients with gastric carcinomas

Expression of sialyl-Tn antigen (STN) was examined by an immunohistochemical method in 85 primary gastric carcinomas. The STN expression occurred in 53 (62.4%) cancers, and the positive staining was correlated with degree of gastric wall and lymph vessel invasion, lymph node metastasis, and stage of tumour. Five-year survival rates of patients with STN-positive cancers (47.2%) were significantly lower than those with STN-negative cancers (84.4%) (P < 0.01), and patients with STN-positive cancers at stage III and stage IV had a worse prognosis. In the cancers with serosal invasion, patients with STN-positive cancer disclosed a significantly poorer prognosis than those with STN-negative cancers (P < 0.01). Therefore, it is suggested that a careful follow-up study and intensive postoperative therapy are needed for patients with advanced gastric cancers with positive STN expression.

Histogenesis and characteristics of gastric-type adenocarcinomas in the stomach

The characteristics and histogenesis of gastric-type adenocarcinomas were studied for endoscopically removed hyperplastic polyps and intramucosal cancers found in surgically resected stomachs (m-cancers). Among 421 hyperplastic polyps, 14 differentiated-type carcinomas were found (HP-cancers). Eleven (78.6%) of these lesions were gastric-type adenocarcinomas. Out of 65 m-cancers, 22 were undifferentiated-type carcinomas and 43 were differentiated-type carcinomas, the latter being classified into 10 gastric-type adenocarcinomas (23.2%) and 13 intestinal-type adenocarcinomas: the remaining 20 were of mixed gastric and intestinal type. The mean age of the gastric-type adenocarcinoma patients did not differ from that of patients with other differentiated-type carcinomas. No appreciable signs of intestinal metaplasia wee noted in HP-cancer polyps. In m-cancers, the degree of intestinal metaplasia of the surrounding mucosa of gastric-type adenocarcinomas tended to be lower than in the other differentiated-type carcinomas, indicating a weak relationship between the histogenesis of gastric-type adenocarcinomas and intestinal metaplasia. Studies by PCNA (proliferating cell nuclear antigen) immunohistochemistry, showed that in over half of the gastric-type adenocarcinomas cases PCNA-positive cells tended to be localized within tumor tissues. In addition, point mutations of the c-Ki-ras gene were detected in 1 gastric-type adenocarcinoma and 2 intestinal-type adenocarcinomas, suggesting the occurrence of a common genetic abnormality.

[Cooperative Study of Surgical Adjuvant Chemotherapy for Colorectal Cancer (fourth report): five-year results after surgery]

In collaboration with 428 institutions nation-wide, comparative studies on the optimal daily dosage of UFT were carried out for non-curative resection cases of colorectal cancer for two years from January 1984 to December 1985. The administration method employed was as follows. Group C received 12 mg/m2 of MMC on the day of operation, followed by 6 mg/m2 every 2 months 6 times, and from the 2nd week after the operation 600 mg/body of UFT was continuously administered every day for 1 year. Group D received 400 mg/body of UFT every day and the same amount of MMC as Group C. Analysis was made of 556 evaluable cases. There was no difference in the survival rate between the two groups. With respect to the dosage per body weight (kg), 8-12 mg/kg of UFT produced good prognoses and less side effects than the group which received more than 12 mg/kg. It seems necessary to administer UFT at its optimal dosage for colorectal cancers.

[Periodic alternating nystagmus in familial congenital cerebellar ataxia]

We noted periodic alternating nystagmus (PAN) in two patients (mother and daughter) who were diagnosed as familial congenital cerebellar ataxia. The mother was 51-year-old and her PAN had about 4 minutes cycle. During eye closure there was a deviation of arms and trunk parallel to the direction of the slow phase of nystagmus. Vestibular stimulation during rotatory and caloric tests disclosed enhanced vestibulo-ocular reflexes, changes of direction and prolonged cycle of PAN. The patient had no visual suppression during caloric stimulation. The daughter was 14-year-old and although she had no spontaneous PAN she had latent PAN by showing changes of direction of nystagmus during the caloric stimulation. She had also no visual suppression during caloric stimulation. From these results the mechanism of PAN could be attributed to the periodic hyperfunction of vestibular nuclei caused by reduced suppression from cerebellar uvula and nodulus.

[Cooperative Study of Surgical Adjuvant Chemotherapy for Colorectal Cancer (third report): five-year results after surgery]

Beginning in January 1984, in collaboration with 357 institutions nationwide, comparative studies on curative resection cases of colorectal cancer and a control group were conducted for 2 years. The following method of administration was employed; Group A received 12 mg/m2 of MMC on the day of operation, followed by 6 mg/m2 every 2 months 6 times. From the 2nd week after the operation, 800 mg/body/day of Futraful was administered for one year. Group B received no treatment. Altogether 2786 cases were collected and, excluding ineligible cases, 2477 evaluable cases were analyzed. There was no difference in either survival rate or disease free rate, but after the bias of background factors was corrected by the hazard model, the disease free rate was better with Group A, and there was a significant difference with the rectum. According to the Dukes classification, in the Dukes C cases with the rectum Group A had higher rate of survival, disease free rate and lower rate of metastasis to the liver and local recurrence of cancer.

Changes in the reactivity and neutralizing activity of a type-specific neutralizing monoclonal antibody induced by interaction of soluble CD4 with gp120

Antibodies directed against the third hypervariable loop-domain (V3 loop) of human immunodeficiency virus type 1 (HIV-1) gp120 inhibit the infection by HIV-1 in a type-specific manner without interfering with the binding of gp120 to CD4. Previous studies demonstrated that soluble CD4 (sCD4) induced the dissociation of gp120 with gp41 and caused conformational changes within the envelope oligomer. We report changes in the binding and neutralizing activity of a monoclonal antibody against the V3 loop after sCD4 binding to gp120. Flow cytometry revealed that a type-specific neutralizing monoclonal antibody against V3 loop of HTLV-IIIB, 0.5 beta, reacted with HTLV-IIIMN-infected cells after exposure to sCD4. When the sCD4-treated HTLV-IIIMN infected cells were analyzed by two-color flow cytometry, most of the CD4-bearing cells were 0.5 beta-positive, indicating that this reactivity of 0.5 beta was associated with the binding of sCD4 to the infected cells. To determine the cross-neutralization by 0.5 beta after exposure to sCD4, HTLV-IIIMN viruses pretreated with sCD4 were used to infect susceptible target cells. The addition of 0.5 beta significantly reduced the p24 antigen production (66.1 +/- 5.9 pg/ml) compared with a control murine IgG (221.3 +/- 15.3 pg/ml). In contrast, no significant reduction in the p24 antigen production was observed by adding the HTLV-IIIMN neutralizing monoclonal antibody, mu 5.5, (209.9 +/- 15.0 pg/ml). Taken together, these results suggest that sCD4/gp120 binding could induce conformational/antigenic changes within the V3 loop that result in the induction of cross-reactivity and cross-neutralizing activity of a type-specific monoclonal antibody.

Duodenal reflux through the pylorus induces gastric adenocarcinoma in the rat

We investigated whether duodenal reflux through the pylorus is involved in the development of gastric cancer. Male Wistar rats weighing 230-250 g were subjected to three types of operative procedures: (i) allowing reflux through the pylorus; (ii) allowing reflux through a gastrojejunal stoma; and (iii) gastrotomy. No carcinogens were given, and the animals were killed 50 weeks after surgery. No cancers were detected in any of the 18 animals with gastrotomy. In contrast, seven (41%) of 17 animals with reflux through the pylorus and four (31%) of 13 animals with reflux through the stoma had adenocarcinoma. Differences in the incidence between both reflux groups and the gastrotomy group were significant (P < 0.01 and P < 0.05 respectively). All of the adenocarcinomas developed in the pyloric mucosa near the pylorus in the animals with reflux through the pylorus, and in the oxyntic mucosa near the stoma in those with reflux through the stoma. Adenocarcinomas appeared as a polyploid mass with or without slight central erosion. Most of the adenocarcinomas were of the well-differentiated tubular type, and the others were of the mucinous type. No differences in either the histologic type or depth of invasion of the adenocarcinoma were recognized between the two duodenogastric reflux groups. Precancerous or paracancerous lesions, such as adenoma, adenocystic proliferation, and stomal pseudopyloric metaplasia, were more frequently found in the same region as the adenocarcinomas. These findings suggest that duodenogastric reflux in the rat has potent carcinogenic activities not only in the oxyntic mucosa through the stoma, but also in the pyloric mucosa through the pylorus.

Purification and characterization of a low M(r) GTP-binding protein, c25KG, from human platelet membranes

A low M(r) GTP-binding protein with a M(r) of 26,000 has been purified from a sodium cholate extract of human platelet membranes by using an antibody raised against a synthetic peptide of c25KG, which was previously purified from human platelet cytosol (Nagata, N., et al. (1989) J. Biol. Chem. 264, 17000-17005). The M(r) of membranous c25KG (m-c25KG) was slightly higher than that from cytosolic c25KG (M(r) 25,000) and calculated to be 26,000. It was suggested that m-c25KG contains an equimolar amount of GDP. The purified protein could bind approx. 1 mol of [35S]guanosine 5'-O-(thiotriphosphate)(GTP gamma S)/mol of protein, with a Kd value of 50 nM. [35S]GTP gamma S-binding to this protein was inhibited by GTP and GDP, but not by ATP and ADP, showing that the binding is specific for guanine. In the presence of 10 mM Mg2+, the dissociation of [8,5'-3H]GDP from the m-c25KG occurred with a rate of 0.01 min-1. The rate of release of Pi from [gamma-32P]GTP-bound m-c25KG was calculated to be 0.03 min-1. These results indicate that c25KG is also present in membrane fraction of human platelet which has very similar biochemical properties in those of the cytosolic type.