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Biomedical subjects

G Mazzotti

Publications and source records attributed to G Mazzotti.

At least 73 records · Page 4Linked to original sources
PubMed1989

Motor effects of locally administered pinaverium bromide in the sigmoid tract of patients with irritable bowel syndrome.

The effects of pinaverium bromide, a non-absorbable antispasmodic agent, administered locally, on sigmoid-rectal motility was investigated in 20 patients with irritable bowel syndrome. The influence of either pinaverium (10 subjects) or placebo (10 subjects) on a neostigmine-induced increase of sigmoid pressure was assessed and compared by means of computerized electromanometry. The drug was found to counteract significantly the motor effects of neostigmine, thus appearing to be an effective compound for the treatment of functional disorders of the colon.

Adult↗
PubMed1988

Gradient fractionation of cycling and resting cells monitored by BrdUrd incorporation.

A number of techniques are currently employed for the fractionation of heterogeneous cell populations or for the separation of cells in different phases of their cycle. With the development of osmotically inert colloidal silica particles media, density gradient centrifugation became an established method for the separation and purification of cells and subcellular particles. We have applied this technique to the separation of cycling from resting Friend erythroleukemia cells, to obtain purified populations for further biological assays. The flow cytometric analysis of DNA content of the different fractions obtained by the gradient and stained with Propidium Iodide (PI), showed the S compartment highly concentrated in the 1.073/77 g/ml interface, while the upper levels of the gradient were highly enriched of cells in G1 phase. Moreover, the dual parameter analysis of DNA content by means of Bromodeoxyuridine (BrdUrd) incorporation and PI staining, showed that part of the cells in the 1.067/73 fraction represented the early S phase even if their DNA level, measured on the basis of PI fluorescence was within the diploid cell cluster. This method seems to be suitable to obtain pure cell fractions even when dealing with numerically large populations.

Animals↗
PubMed1988

Lipid mediated signal transduction in the cell nucleus.

Cell growth and differentiation can be affected by the transduction of extracellular signals involving cyclic nucleotides, inositol phospholipids and phospholipid dependent protein kinase C systems. Since we previously reported existence of lipids inside the nucleus and nuclear fractions, it seems of interest to examine the possible presence of the cascade of inositol lipids in isolated nuclei as well as the presence of the protein kinase C, whose activity is tightly related to the phosphoinositide cycle, and requires the presence of phosphatidylserine, which has been previously demonstrated to deeply affect nuclear structure and function. Here we show that highly purified nuclei from both rat liver and Friend cells, free of nuclear membrane, can incorporate radiolabel from ATP-[32P] into phosphatidic acid, phosphatidyl-inositol phosphate and phosphatidylinositol (4', 5')bisphosphate. The degree of radiolabelling of phosphatidylinositol bisphosphate is highly dependent on the state of differentiation of the cells. Moreover, a doublet of immunoreactive bands has been identified in rat liver nuclei by means of a polyclonal antibody against protein kinase C. The two polypeptides appear to be tightly bound to the nuclear matrix. These two forms of the enzyme might be translational products specifically located in the nucleus, involved in the transduction to the genomic apparatus of regulatory signals generated by growth factors and tumor promoters.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Estimation of radiation dose produced by impurities in nuclear medicine studies using Tl-201 chloride].

Radionuclide impurities can significantly increase the absorbed dose in Nuclear Medicine examinations. The aim of this study is to evaluate the dose of Tl-200 and Tl-202 in patients injected with Tl-201 for myocardial scintigraphy. All relevant nuclear and biological data are reported; Thallium distribution in the body is then discussed with particular regard to the gastro-intestinal tract. Since MIRD Committee has not published "S" values for Tl-200 and Tl-202, these have been calculated by a computer code and are reported. The absorbed dose for these Thallium isotopes is presented. For example, kidney doses in Gy/GBq are 0.29 (Tl-200), 0.27 (Tl-201) and 0.97 (Tl-202). The total dose increase for a 2% presence of Tl-202 is about 11%.

Digestive System↗
PubMed1985

[Effect of tiropramide chlorhydrate on intestinal transit time in patients with irritable colon syndrome].

The effect of tiropramide hydrochloride--a new spasmolytic drug with calmodulin-independent activity--in correcting alterations of intestinal transit, has been investigated in 40 IBS patients (20 with accelerated and 20 with delayed transit time). Intestinal transit has been evaluated by means of radioopaque markers. Tiropramide hydrochloride, at a dose of 100 mg t.i.d. for 4 weeks, was found significantly more effective than placebo both in normalizing intestinal transit time and in inducing symptomatic relief.

Adult↗
PubMed1983

[Progesterone-induced changes in the endometrium. Ultrastructural studies of castrated, adrenalectomized and hypophysectomized impuberal rats].

Research has been made on the progesterone-induced effects upon endometrium on impuberal rats (either intact, or castrated, or castrated and adrenalectomized, or hypophysectomized) after an acute or a protracted treatment, which were made every third hour all through the day. It resulted that the hormone basically shows two distinct activities. The first one causes a modest awakening of the anabolical functions both in the lining and in the glandular epithelia, which results in the building up of small amounts of lipid and glycogen. The second one involves the lamina propria as well, and brings about morphological effects which can be superposed on those induced by estrogens. The former seems an autonomous activity and can mainly be found after long-lasting treatments. The latter, on the contrary is influenced by the administration time and can be detected only during a.m. treatments whereas it cannot be detected during p.m. and night treatments. Besides it is influenced by the hypophysal activity and in particular by gonadotropins. The possible mechanism of these influences are discussed.

Adrenalectomy↗
PubMed1983

Association between centriole and nuclear matrix in human lymphocytes.

Nuclear matrices, purified from normal and chronic lymphocytic leukemia lymphocytes, exhibit a close association with the centriole. This finding suggests that the nuclear and cytoplasmic skeletal systems are linked by transmembrane connections represented by nuclear matrix constituents. This could account for the observed synchrony between transformations of the centriole and particular nuclear events which take place during the cell cycle and suggests that the nuclear matrix, besides being involved in DNA replication and chromosome condensation, should affect the centriole cycle which controls the cytoskeleton organization.

Cell Division↗
PubMed1982

Role of chromatin phospholipids on template availability and ultrastructure of isolated nuclei.

The influence of phospholipid vesicles has been tested on isolated nuclei by evaluating the endogenous DNA-dependent RNA polymerase and the chromatin ultrastructure. Negatively charged phosphatidylserine liposomes have a stimulating effect on RNA synthesis, while the vesicles obtained with the neutral sphingomyelin, phosphatidylethanolamine and phosphatidylcholine, and the acidic phosphatidylinositol, are inhibitory. The enhancement of transcription by phosphatidylserine seems to be due to both elongation and initiation of RNA transcripts and very likely depends on interactions of the lipid with the template rather than with the enzymes. The morphological analysis indicates deep changes of the chromatin organization, mainly concerning the size and distribution of the fibers, without any variation of the nuclear volume. The rearrangement of the chromatin could account for the variations of the template availability for RNA synthesis induced by the vesicles and might be associated with changes of the nuclear matrix.

Animals↗
PubMed1981

[Characterization of the convoluted seminiferous tubule wall. II. Ultrastructural alteration after testis retention in the abdominal cavity].

An ultrastructural analysis has been carried out on the seminiferous tubules after different periods of stay of the rat testis in the abdominal cavity. With respect to control rats, no changes are detectable after 5 days, while after 15 and 30 days considerable modifications take place. A number of cellular features are modified, such as the nuclear shape and the perinuclear vesicles, while the cytoplasmic filaments show a less ordered appearance. In addition, the extracellular amorphous matrix undergoes a large increase, due either to an enhanced production or to a reduced turnover related with a lowered cell activity.

Animals↗
PubMed1981

[Karyotype analysis during development of chronic myelocytic leukemia].

We report cytogenetic data concerning 9 patients with chronica granulocytic leukemia and eosinophilia at the onset and during the chronic phase of the disease before the blastic crisis. The cariotype analises in the intermediate phases allowed to determine the first changes which could be involved in the evolutionary events of the disease up to the moment in which the typical markers of the blastic crisis can be found.

Adult↗
PubMed1981

[Characterization of the convoluted seminiferous tubule wall. I. Ultrastructural aspects after the ligation of the vas deferens and the efferent tubules].

The structure of the wall of the rat seminiferous tubules has been studied by electron microscopy. No significant modifications have been revealed after the ligature of the vas deferens while on the contrary the ligature of the efferent ductules produces a reduction of the contractile filaments and of the pinocytosis vesicles, as well as an increase of the amount of collagen fibers in the basal membrane.

Animals↗
PubMed1981

Improved method for determination of high-density-lipoprotein cholesterol II. Enzymic determination of cholesterol in high-density lipoprotein fractions with a sensitive reagent.

A reagent is described for the colorimetric enzymic determination of high-density-lipoprotein (HDL) cholesterol. The reagent can be used with HDL fractions isolated by the various methods of precipitation of low- and very-low-density lipoproteins we investigated. The considerable sensitivity obtained by use of Barham-Trinder's reaction allows the sample/reagent volume ratio to be decreased to 1:80, and major interferences thus eliminated. The response is linear from 100 to 2000 mg of HDL cholesterol per liter. The maximum CV obtained in precision tests was approximately 1% within series and approximately 3% between series. Most of the bilirubin interference is eliminated by adopting a reaction pH of 6.1. Because of its sensitivity, the reagent is particularly suitable for use with HDL fractions isolated after precipitation with polyethylene glycol 6000, which are characterized by a marked dilution. HDL cholesterol determination with the proposed reagent is accurate and precise. Values obtained are in line with those provided for by the Abell-Kendall method. The method can easily be automated.

Aminopyrine↗
PubMed1980

[Karyologic analysis in erythroleukemia].

We report the cytogenetic data of two patients with erythroleukemia showing the chromosome Ph'. In one case the chromosome Ph', as revealed with the GTG band technique was the result of a translocation involving the chromosomes 19 and 22. The aim of this work is to provide more contribution to the knowledge of the origin of the Ph' and to give data in the field of this disease for which few cytogenetic data are available after the introduction of the banding techniques.

Aged↗
PubMed1979

Effect of phosphatidylcholine vesicles on the activity of DNA polymerase-alpha.

Phosphatidylcholine vesicles stimulate the activity of the DNA polymerase-alpha from calf thymus. This effect is dependent upon the way of addition to the Mg ions, and the extent of the 3H-dTTP incorporation is closely related to the concentration of the vesicles. A role of phospholipids on the activity of the DNA-related enzymes is suggested.

Animals↗