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Biomedical subjects

M Giuliano

Publications and source records attributed to M Giuliano.

At least 91 records · Page 5Linked to original sources
PubMed1987

Effect of broad-spectrum parenteral antibiotics on "colonization resistance" of intestinal microflora of humans.

Studies with animals have shown that the normal intestinal microflora protects against colonization by new strains ("colonization resistance") and that this protective effect may be related to the anaerobic component of the microflora. However, colonization resistance has not been shown in humans. We administered cefoxitin, piperacillin, cefoperazone, and aztreonam intravenously to healthy subjects for 9 days and monitored the acquisition of new isolates in the fecal flora. Seven of sixteen antibiotic-treated subjects but none of four untreated controls became colonized by gram-negative bacilli. However, there was no correlation between colonization and the particular drug given or the extent of suppression of anaerobes or of any other component of the fecal microflora. Cefoxitin and piperacillin were associated with the greatest increases in the numbers of drug-resistant bacteria and in fecal beta-lactamase content. The results of this study support the concept that colonization resistance occurs in humans and is diminished by antibiotic administration but fail to support the hypothesis that resistance is related to the anaerobic microflora.

Anti-Bacterial Agents↗
PubMed1986

Report of a family with hereditary site-specific colon cancer.

A large family with a high prevalence of colorectal cancer, presenting the major features of hereditary site-specific colon cancer (i.e., autosomic dominant model of heredity, absence of associated adenomatous polyposis, prevalence of right-sided colonic lesions, and young age of the patients) is described. The lack of association with solitary adenomatous polyps, the higher survival rate of patients with left-sided colon cancer, and the absence of extracolonic tumors were peculiar characteristics of this family. These data, in agreement with other reports, appear to suggest that the inherited colon cancer syndromes are not a single entity, but a group of related entities linked by their familial occurrence.

Adenocarcinoma↗
PubMed1986

Isolation of Clostridium difficile from human jejunum: identification of a reservoir for disease?

The possibility that the small intestine may represent a reservoir for Clostridium difficile was studied, using segments of human jejunum collected at necropsy. Our results (three of 100 specimens positive for C difficile culture) support the hypothesis that C difficile can be found in human jejunum and that it adheres to the normal mucosa as a resident bacterium. These findings suggest that gastrointestinal disease caused by C difficile has an endogenous origin.

Aged↗
PubMed1985

Nucleoside phosphotransferase in animal tissues. Tissue distribution and kinetic properties.

Amphibian, avian and mammal tissues contain a nucleoside phosphotransferase clearly different from those previously described in vegetables and bacteria. Whatever the animal source, the enzyme showed many similar characteristics as far as substrate specificity, dependence upon Mg2+, instability at 37 degrees C, and the protecting effect of nucleotides were concerned. Moreover, when submitted to gel filtration, the enzyme behaved in all cases as a dissociable high molecular weight protein, whose degree of association was controlled by nucleotides. In amphibian and avian tissues multiple forms of the enzyme seem to be present which differ for the substrate concentration at half-maximal velocity (S0.5); the concentration of nucleotide effector which affords half-maximal protection at 37 degrees C (P0.5); and the Hill coefficient for monophosphate donor. Within each single species, the higher the interaction coefficient was, the lower S0.5 and P0.5 values were. In mammalian tissues one form of nucleoside phosphotransferase seems to prevail where cooperative interactions are almost absent and whose S0.5 as well as P0.5 values do not vary significantly from one tissue to another.

Animals↗
PubMed1985

[Evaluation of various methods of preserving samples for the study of intestinal microflora].

Intestinal microflora changes in ten adult and healthy subjects after storage of specimen with different modalities, temperatures and times were evaluated quantitatively and qualitatively. Aerobic components (Enterobacteriaceae, Enterococcus, Staphylococcus and Bacillus spp.) did not show considerable variations of concentration in all maintenance conditions. Anaerobic components showed different capacity of survival for every researched genus: Clostridia and Lactobacilli, even kept frozen for one month in glycerol broth at -70 degrees C, maintained a stable viable count; Bacteroides, Fusobacteria, Veillonellae and Peptostreptococci were found stable after one week, while after one month showed a loss of concentration superior to 4 Log; Eubacteria were found remarkably reduced after seven days and completely lost after one month.

Adult↗
PubMed1984

The inhibitory effect of D-glucosamine on thymidine kinase in chick embryo retinas and HeLa cells.

D-Glucosamine markedly inhibits thymidine incorporation into the TCA-insoluble fraction and thymidine kinase activity in HeLa cells. Both the inhibitory effects are also observed in isolated retinas of chick embryos. In this case the inhibitory effects are age-dependent and the magnitude of the responses decreases with embryonic development. In addition the time of exposure to D-glucosamine which is necessary to reveal the inhibitory effect on thymidine kinase increases with the age of the embryos.

Age Factors↗
PubMed1984

The purification and properties of nucleoside phosphotransferase from mucosa of chicken intestine.

Nucleoside phosphotransferase (nucleotide: 3'-deoxynucleoside 5'-phosphotransferase, EC 2.7.1.77) has been purified from chicken intestine mucosa to apparent homogeneity. The enzyme is represented by a multisubunit protein at different degrees of association. It can dissociate into a component with a marked fall in catalytic activity. The associated forms are similar to the enzyme previously purified from chick embryo as regards: substrate specificity both with respect to nucleoside monophosphate donors and to deoxyribonucleoside acceptors; sigmoidicity in the rate curve with a variable phosphate donor; instability to heat, dilution and lowering of pH; the activating and protecting effect of nucleotides, particularly the diphosphate forms. The dissociated form displays lower Vmax and higher S0.5 than the associated ones; and the Hill constants are always about 1. With this form, nucleotides show only a modest activating effect and do not protect. Mg2+, Mn2+ or Co2+ are required for catalytic activity, whereas the protective effect of nucleotides is independent of divalent metals. Inorganic phosphate stabilizes associated forms of the enzyme, but inhibits its activity by competing with nucleotide effectors. The enzyme behaves also as a phosphohydrolase, particularly with respect to deoxyribonucleoside monophosphates; deoxyuridine and deoxythymidine inhibit hydrolytic activity.

Alcohols↗
PubMed1984

[In vitro activity of several cytostatic drugs against aerobic and anaerobic intestinal bacteria].

The human normal intestinal flora prevents the colonization of exogenous bacteria, maintaining a constant microecology: this property is called "colonization resistance". In leukemia patients antibiotics used for prevention and/or therapy of infectious episodes can alter the intestinal microecology, so that the gut can represent the trigger zone for generalized septicemia. Moreover cytotoxic drugs used in these patients can favour intestinal disturbances. In our study we evaluated the in vitro activity of three commonly used antineoplastic drugs (Daunorubicin, Cytosine arabinoside, Methotrexate) against aerobic and anaerobic intestinal bacteria and Clostridium difficile that is the aetiological agent of pseudomembranous colitis. Daunorubicin proved to be the most active inhibiting, in concentration ranging from 16 to 128 micrograms/ml, 50% of Bacteroides strains and 90% of Clostridium difficile and Enterococci strains tested. Methotrexate showed activity only against some Bacteroides strains, while Cytosine arabinoside had no activity at all. We conclude that in these patients the use of these drugs may represent another factor of risk altering the intestinal flora and so lowering the colonization resistance.

Bacteria, Aerobic↗
PubMed1983

The effects of glucocorticoids on thymidine kinase and nucleoside phosphotransferase during development of chicken embryo retina.

Thymidine kinase in chick embryo retina reaches its highest values on the 8-10th day of development, then declines reaching the lowest value at hatching. The rate of DNA synthesis essentially follows this activity while, in contrast, nucleoside phosphotransferase increases progressively during development. Glucocorticoids at 5 X 10(-6) M lower the level of thymidine kinase in isolated retinas of chick embryo. The most effective steroid was hydrocortisone. The effect was observed in retinas from 8-18-day-old chick embryo and, except on the 8th day, was always of the same magnitude. We suggest that a glucocorticoid can be the natural factor responsible for the marked fall in thymidine kinase during development. Brief periods of exposure to steroids increase nucleoside phosphotransferase activity in isolated chick embryo retinas. When the exposure was longer than 3 h this activity was also clearly decreased. We conclude that other factors are responsible for the natural increment which occurs for this activity during development.

Animals↗
PubMedDate not supplied

Post-traumatic macular break associated to congenital optic disc pit and pre-existing sensory macular detachment.

BACKGROUND: Optic disc pits represent a rare congenital abnormality frequently associated with macular detachment. Several theories on the pathogenesis of the detachment have been proposed, but the issue still remains unclear. Treatment remains speculative as well; advocated treatments include eye-patching, bed rest, steroids, laser photocoagulation, pars plana vitrectomy with fluid-air exchange and optic nerve sheath decompression. METHODS: The Authors report on the case of an optic pit with associated macular detachment which developed an inner layer macular hole and, after an apparently insignificant skull trauma, a large macular break. The patient underwent a standard three-port pars plana vitrectomy, fluid gas-exchange, posterior scleral buckling and laser treatment. RESULTS: Twelve months after surgery the retina was flat, posterior buckling was evident and laser treatment pigmented. Visual acuity was 20/600. CONCLUSIONS: The presence of strands of condensed vitreous strands crossing the posterior lacuna and exerting traction over the macula and optic disc, support the theory of a possible tractional role of anomalous vitreous adhesion in the pathogenesis of the detachment and macular break. Anomalous vitreous adhesion over the posterior retina could be related to the malformative genesis of the syndrome, and the anomalous persistence of the Cloquet's canal or primary vitreous could be responsible for the traction.

Adolescent↗
PubMedDate not supplied

Synergistic cytotoxic interactions between sodium butyrate, MG132 and camptothecin in human retinoblastoma Y79 cells.

This paper studies the effects caused in human retinoblastoma Y79 cells by treatment with combinations of sodium butyrate, the inhibitor of topoisomerase I camptothecin and the inhibitor of 26S proteasome MG132. The combination of sodium butyrate and camptothecin resulted in a strong synergistic cytotoxicity, as revealed by combination indices of 0.77 and 0.52 calculated at IC(50) and IC(75). Synergistic interactions were also demonstrated for combinations of sodium butyrate and MG132, camptothecin and MG132 and for a combination of all three compounds. The cytotoxic effects observed after the combined treatments can be considered a consequence of apoptosis, as suggested by the appearance of morphological signals of apoptosis and by the activation of caspase-3 with degradation of poly-ADP ribose polymerase and lamin B. Treatment of Y79 cells with sodium butyrate alone lowered the levels of p53, E2F-1 and Bcl-2. The addition of MG132 to sodium butyrate counteracted the effect on p53 only, while the addition of camptothecin to sodium butyrate counteracted the effect on both p53 and E2F-1. The treatment of Y79 cells with the triple combination increased the level of p53, decreased that of Bcl-2, while the level of E2F-1 was not modified. We suggest that the effects exerted on the levels of these regulatory proteins can explain the synergistic interactions demonstrated between sodium butyrate, camptothecin and MG132.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

SV40, JC and BK expression in tissue, urine and blood samples from patients with malignant and nonmalignant pleural disease.

BACKGROUND: Polyomaviruses are expressed in both human tumors and immunodepressed patients. Malignant and nonmalignant pleural effusions create an environment that could favor the expression of opportunistic viral infections. We studied if SV40, JC, and BK viral DNA can be amplified from biopsies obtained from different pleural diseases. MATERIALS AND METHODS: DNA was extracted from mesotheliomas (MM), nonspecific inflammatory and tubercular pleural biopsies, blood and urinary sediments from patients with MM, and pleural effusion cytological specimens. SV40, JC and BK viral early regions were amplified by PCR and analyzed by Southern Blot hybridization with specific probes. RESULTS: SV40 was positive in 9/23 MM, 5/18 tubercular and 1/7 nonspecific inflammatory biopsies, and 5/12 pleural effusion cytological specimens. JC was positive in 2/23 MM and in 7/15 urinary sediments. All blood samples were negative and BK was also negative in all samples. CONCLUSIONS: Tissue specific factors, characteristic of MM and TB, may contribute to expression of SV40 in these diseases.

BK Virus↗