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F De Ritis

Publications and source records attributed to F De Ritis.

At least 19 recordsLinked to original sources
PubMed1995

Transglutaminase in azoxymethane-induced colon cancer in the rat.

A widespread from of transglutaminase, tissue transglutaminase, has been identified in a number of mammalian cell types, both normal and transformed cells; its biological role is not well understood. We investigated the effect of experimentally induced colon cancer on transglutaminase activity in the rat. Azoxymethane (15 mg/kg for six weeks), given by a course of weekly intraperitoneal injections, produces tumors almost exclusively confined to the intestinal tract. Transglutaminase activity was assayed on tissue homogenates both during the period of treatment and, when the cancer had developed, on tumor tissue and on microscopically uninjured adjacent tissue. A transient proliferative phase was present in the intestine during azoxymethane treatment: in this phase we found a coincidentally increased transglutaminase levels. Transglutaminase activity in tumors of both small and large intestine was significantly higher than in adjacent tissue. Immunohistochemistry revealed higher levels of transglutaminase in tumors, mainly localized in the extracellular matrix, than in adjacent tissues, where it was widely distributed. The present study shows that transglutaminase, besides its potential role in intracellular process during early proliferative phase of carcinogenesis, may also play an important role in matrix processing during tumor growth and differentiation.

Adenocarcinoma↗
PubMed1994

Butyrate, mesalamine, and factor XIII in experimental colitis in the rat: effects on transglutaminase activity.

BACKGROUND/AIMS: Butyrate and factor XIII may improve ulcerative colitis; they also affect tissue and serum transglutaminase levels. We investigated the therapeutic potential of sodium butyrate and factor XIII and the role of transglutaminase during mucosal repair in experimental colitis. METHODS: Rats with induced colitis were treated with sodium butyrate, mesalamine, sodium butyrate plus mesalamine, or saline enemas. Thromboxane B2 was monitored as index of inflammation. In a fifth group, the effectiveness of intravenous Factor XIII was assessed. RESULTS: Sodium butyrate, alone or plus mesalamine, reduced histological activity from 13.7 +/- 1.7 (saline) to 2.5 +/- 1.3 and 2.3 +/- 1.1 (P < 0.01), respectively. Transglutaminase, reduced in the colons of the saline group (783 +/- 157 vs. normal 1800 +/- 192 mU/g; P < 0.01), returned toward normal values in the sodium butyrate or sodium butyrate plus mesalamine groups (1390 +/- 228 and 1226 +/- 172 mU/g, respectively; P < 0.01 vs. saline). Furthermore, sodium butyrate plus mesalamine reduced thromboxane B2 levels by day 5 (0.92 +/- 0.16 vs. saline 1.85 +/- 0.34 ng/mL; P < 0.05). Factor XIII therapy improved the histological picture (2.7 +/- 2.1 vs. saline 13.8 +/- 1.7; P < 0.01) and increased transglutaminase levels both in serum (2.81 +/- 0.11 vs. saline 1.45 +/- 0.09 mU/mL; P < 0.01) and in colon (1503 +/- 127 vs. saline 747 +/- 103). CONCLUSIONS: Sodium butyrate and factor XIII improve colitis, sodium butyrate plus mesalamine reduce early thromboxane B2 synthesis, and transglutaminase(s) plays a role in ulcer healing.

Aminosalicylic Acids↗
PubMed1983

Diminished active T rosette levels and increased spontaneous B lymphocyte blastogenesis in hepatitis B virus positive chronic active hepatitis.

The present investigation was designed to detect abnormalities in CMI and the presence of polyclonally activated B cells in patients with HBV positive CAH. We studied the peripheral levels and 3H-thymidine incorporation of three lymphocyte subsets: B lymphocytes, as well as two T cell subsets that are either active or late rosetters with high and low affinity receptors respectively for sheep red blood cells (SRBC). In patients the level of peripheral T active cells was decreased, but they exhibited elevated B cell activation. There was also a significant correlation between the decreased levels of T active cells and increased 3H-thymidine incorporation by B lymphocytes. Taken together, our results are consistent with the hypothesis that patients with HBV positive CAH have a severe impairment of T cell function that may lead to an abnormal B cell activation. The increased B cell activity may account for the presence of circulating immune complexes and the variety of autoantibodies often observed in patients with HBV positive CAH.

Adult↗
PubMed1979

HBsAg uptake by macrophages in vitro: an immunofluorescence study.

The uptake of HBsAg by in vitro cultured macrophages was studied by immunofluorescence method. Intracytoplasmic fluorescent particles appeared 3 h after the contact with HBsAg-positive serum, while after 24-48 h only a few cells contained these particles, which are probably destroyed within the cytoplasm.

Animals↗
PubMed1979

Influx of glycyl-proline and free amino acids across intestinal brush border of phenobarbital-treated rats.

In a previous study the authors have shown that treatment with phenobarbital in the rat is followed by a generalized increase of amino acid concentration in the plasma. In order to better clarify this phenomenon, the effect of phenobarbital on intestinal protein absorption was now studied by measuring the influxes of Glycyl-L-Proline, L-Phenylalanine, L-Lysine and L-Glutamic acid across the brush border of jejunum and ileum in rats treated with phenobarbital for two or four days. No significant changes of these influxes were observed in the treated animals as compared to the controls, hence suggesting that the effect of phenobarbital on plasma levels of free amino acids is not mediated by an effect on intestinal absorption. The rate of Glycyl-Proline influx as compared to those of amino acid influxes suggests the occurrence of a carrier-mediated transport process for this dipeptide in the rat intestine as previously shown in the rabbit.

Amino Acids↗
PubMed1978

[Clinical enzyme diagnosis in chronic hepatitis. Possibilities and limitations (author's transl)].

The determination of enzyme activity in serum for the diagnosis of chronic hepatitis has become increasingly popular. According to the author's experience serum aminotransferase is raised in about 100% of cases of chronic active hepatitis and also in active cirrhosis, but in only about 70--80% of persisting hepatitis or in moderately active chronic hepatitis. They are frequently normal in inactive cirrhosis. After aminotransferases the alkaline phosphatase is of great importance for the differential diagnosis of icterus. If aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase are determined at the same time, every cholestatic icterus can be diagnosed with certainty.

Alanine Transaminase↗
PubMed1978

Pattern and concentration of free amino acids in the plasma and liver tissue of phenobarbital-treated rats.

The pattern and concentration of free amino acids in the plasma and liver tissue of phenobarbital-treated rats was investigated. In phenobarbital-treated rats, there was a significant plasma increase of the total concentration of free amino acids. No significant change in liver free amino acid concentration was observed because of the contemporaneous and general increase in liver size which does not allow observation of any percentual variation in amino acid concentration.

Amino Acids↗
PubMed1977

Free amino acids in plasma during experimental infection of mice with the MHV-3 strain of mouse hepatitis virus.

The concentrations of total free amino acids, single free amino acids, urea, and ammonia were determined in plasma of mice during experimental infection with the MHV-3 strain of mouse hepatitis virus. Analysis of free amino acids was done by ion-exchange resin chromatography under conditions that allowed the use of a single chromatographic column, separation of glutamine and asparagine, and an accelerated rate of chromatography. The results showed that as early as 6 hr after infection there was a decrease in the concentration of several free amino acids as well as in the total concentration of free amino acids in plasma. For most of the amino acids the decrease persisted until 48 hr. Only at 72 hr, during severe cytolysis, did the concentration of amino acids increase significantly. It is suggested that the decrease during the initial phases of the infection may be due to a thermolabile factor that is produced by circulating leukocytes and that effects a flow of free amino acids from the plasma toward the liver. The final increase in concentration of several free amino acids reflects the cytolytic damage to the liver caused by the virus.

Amino Acids↗
PubMed1975

[Radioimmunoquantization of the HBAg in clinical liver diseases].

The two-step direct radioimmune test RIA used to detect hepatitis B virus associated antigen (HBsAg) appeared to be more sensitive than other immunologic assays. RIA demonstrated as HBsAg positive 90% of 20 patients with posttransfusion hepatitis; 88% of 50 patients with acute viral hepatitis; 100% of 13 patients with chronic active hepatitis and 35% of 20 patients with cirrhosis; on the other hand with positivity for HBsAg in the same patients appeared to be lower by AGD, CIEP and CF. The quantitation of HBsAg by RIA has been performed with a dose response curve obtained by use of HBsAg (ad) standard. The quantitative HBsAg data of an eight week follow-up of fully recovered 15 patients with acute B-hepatitis are reported. In the first week it appeared a distribution of the HBsAg levels into three classes of values. The concentration of HBsAg in the serum became lower week by week and in the 8th week the HBsAg was no longer detectable. The radioimmunoquantitation of HBsAg in the serum of patients suffering from chronic active hepatitis and cirrhosis showed levels of antigenaemia ranging between 17 and 5100 ng ad equivalent/ml. The use of a dose response standard curve in order to quantify HBsAg in the serum represents a further increased sensitivity of RIA.

Acute Disease↗
PubMed1975

Hepatitis B virus antigen quantitation by radioimmunoassay (RIA) in viral hepatitis and in chronic liver diseases.

The incidence of HBAg in viral hepatitis, in chronic active hepatitis and in cirrhosis has been investigated by using immunological methods and a solid-phase radioimmunoassay. RIA demonstrated as positive: 90% of 20 patients with posttransfusion hepatitis; 88% of 50 patients with acute viral hepatitis; 100% of 13 patients with chronic active hepatitis and 35% of 20 patients with cirrhosis; whereas the frequency of HBAg in the same patients appeared to be lower by AGD, CIEP and CF. The measure of antigenaemia has been obtained by use of HBAg (ad) dose response standard curve. The quantitative HBAg data of an eight-week follow-up of fully recovered 15 patients with acute hepatitis are reported. In the first week it appeared a distribution of the HBAg levels into three classes of values. The concentration of HBAg in the serum became lower week by week and in 8th week the antigen was no longer detectable. The radioimmunoquantitation of HBAg in the serum of patients suffering from chronic acitve hepatitis and cirrhosis showed wide levels of antigenaemia ranging between 17 and 5100 ng ad equivalent/ml. The use of a dose response standard curve in order to quantify HBAg in the serum represents a further increased sensitivity of RIA.

Acute Disease↗