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Biomedical subjects

M Greco

Publications and source records attributed to M Greco.

At least 109 records · Page 6Linked to original sources
PubMed1995

Sexually differentiated response to choline in choline deficiency and ethionine intoxication.

A sex difference exists in the response of rats to a choline deficient diet and to ethionine intoxication. Female rats are less susceptible than males to the acute effects of choline deficiency, such as fatty liver and impaired secretion of triglycerides into blood plasma, while they are more susceptible to inhibition of liver protein synthesis and triglyceride accumulation by ethionine. These differences have been ascribed to sex differences in the biosynthesis of phosphatidylcholine in the liver of rats. The available data indicate that females are more dependent than males on the stepwise methylation of phosphatidylethanolamine rather than the direct incorporation of preformed choline. Continuous prefeeding with choline for three weeks was able to shift the female pattern of response to choline deficiency and ethionine intoxication towards that observed in males; thus, choline caused accumulation of hepatic triglycerides and a decrease in plasma triglycerides after choline deficiency, while it protected against ethionine induced triglyceride accumulation and protein synthesis inhibition in the liver. These results suggest that choline prefeeding in females makes them more dependent on choline availability and, thus, more susceptible to a choline deficient diet and less sensitive to ethionine intoxication, as are males. No effect of choline was observed in either choline deficient or ethionine intoxicated male rats.

Animals↗
PubMed1994

Increase of both transcription and translation activities following separate irradiation of the in vitro system components with He-Ne laser.

To gain insight into the mechanism by which cell irradiation with low power continuous wave He-Ne laser (632.8 nm) causes a general stimulation of biosynthetic properties, separate components of transcription and translation systems were irradiated (energy dose 2 Joules/cm2; laser power 12 mW) with measurements made of in vitro RNA and protein synthesis. In addition, all tested components were investigated with respect to influence of laser irradiation on their conformation, as spectroscopically monitored. In all cases an increase in both transcription and translation activities was found with a significant change in absorbance/fluorescence spectra.

Animals↗
PubMed1994

Liposome encapsulation improves the effect of antifibrotic agent in rat lung fibrosis.

We studied whether the therapeutic efficacy of the antifibrotic agent cis-4-hydroxy-L-proline (cHyp) in preventing bleomycin-induced pulmonary fibrosis in rats is enhanced by intratracheal delivery in liposomes. Dual-radiolabeled liposomes were used to study the distribution and stability of liposomes after intratracheal instillation. Lung retention was > 20% 1 wk after intratracheal instillation of 9 mumol phospholipid, and liposomes were intact as indicated by the ratio of the lipid and aqueous-phase markers remaining unchanged. For the fibrosis study, groups of rats were instilled with 1.2 U bleomycin (Bleo) and treated 1 and 2 wk later by single intratracheal instillation of test compounds. The control group received 0.3 ml saline (Bleo/sal). The treated groups received 9 mumol phospholipid in 0.3 ml of the following liposome preparations: empty liposomes (Bleo/lip), liposomes and 100 mg/kg of free unencapsulated cHyp (Bleo/lip/cHyp), and 100 mg/kg of liposome-encapsulated cHyp (Bleo/lip-cHyp). At 3 wk, fibrosis (mg hydroxyproline/g weight lung) by groups was as follows: control, 2.6 +/- 0.1 (SEM); Bleo/sal, 3.2 +/- 0.1, Bleo/lip, 3.2 +/- 0.1, and Bleo/lip/cHyp, 3.1 +/- 0.1, p < 0.05 compared with control; Bleo/lip-cHyp, 2.6 +/- 0.1, p < 0.05 compared with Bleo/sal, n = 3 to 6. Histologic grading of fibrosis did not show decreased fibrosis in the Bleo/lip-cHyp group, probably because of the focal nature of the fibrotic lesions. We conclude that cHyp encapsulated in liposomes prevents bleomycin-induced fibrosis by biochemical measurements. Delivery of antifibrotic agents to the lung in carrier vehicles promotes retention and may enhance their efficacy in treating bleomycin-induced pulmonary fibrosis.

Animals↗
PubMed1994

Increase in <--H+/e- ratio of the cytochrome c oxidase reaction in mitochondria irradiated with helium-neon laser.

In order to gain a degree of insight into the mitochondrial component/s responsible of the mitochondria-red light interaction, isolated rat liver mitochondria were irradiated with a Helium-Neon laser (energy dose 2 Joules/cm2, light power 10 mW) and measurements made of the activity of cytochrome c oxidase. A low, but statistically significant increase in the oxygen uptake was found, as polarographically measured, in the presence of rotenone and antimycin A, with ascorbate and TMPD used as substrate pair. Measurements were also made both of the electron transfer and of proton pumping activity: as a result of a major stimulation in the proton pumping activity, about 55% increase of <--H+/e- ratio was found in irradiated mitochondria.

Animals↗
PubMed1994

Surgical pitfalls after preoperative chemotherapy in large size breast cancer.

Preoperative chemotherapy in 226 women with large breast cancers reduced tumour size sufficiently for breast conservation surgery, according to our criteria, in 203 patients (90%). After 50 months' mean follow-up there were 13/203 local relapses (5.3%). This approach is therefore effective but only if the breast can be conserved with good aesthetic result, otherwise mastectomy plus reconstruction is preferable. The type of surgery must be decided during operation after careful assessment of tumour regression, resection margins, tumour size in relation to breast size and extent of microcalcifications.

Antineoplastic Agents↗
PubMed1994

Social networks and daily activities of street youth in Belo Horizonte, Brazil. Street Youth Study Group.

Social networks and daily activities of children and adolescents living and/or working on the streets of a large Brazilian city were examined. Drawing on data collected through structured surveys, in-depth interviews, focus group discussions, and field observations, we described street youths' family situation, social resources, institutional experiences, survival activities, and problem behaviors and investigated differences attributable to age, gender, and living situation (at home or on the street). Youngsters who lived at home and worked on the street appeared to be experiencing orderly development despite their impoverished circumstances. Youngsters who lived on the street showed hallmarks of psychological and physical risk, including parental loss, diminished social support, substance abuse, and early onset of sexual activity. Possible implications of these contextual differences for development are discussed, and directions for future research are suggested.

Activities of Daily Living↗
PubMed1993

Activation of mitochondrial DNA replication by He-Ne laser irradiation.

To gain further insight into the effect of He-Ne laser irradiation on the mitochondrial biosynthetic apparatus, DNA synthesis was measured in mitochondria, mitoplasts and mitochondrial matrix fraction irradiated with low power continuous wave He-Ne laser (energy dose 5 Joules/cm2; laser power 12 mW). As a result of irradiation, the amount of alpha-[32P]dATP incorporated in acid insoluble materials was found to increase. Electrophoretic analysis of in vitro synthesised DNA purified from mitochondria, mitoplasts and matrix fraction shows an increase of 50-60% of DNA synthesis in the irradiated samples. These data show that He-Ne laser stimulates the replication of mitochondrial DNA in both intact organelles and soluble matrix fraction, thus suggesting an interaction of laser light with matrix soluble molecule/s.

Animals↗
PubMed1993

Radiotherapy after breast-preserving surgery in women with localized cancer of the breast.

BACKGROUND AND METHODS: Conservative surgery and radiotherapy have become well-established treatments for breast cancer, and many trials in progress are attempting to define the most acceptable type of procedure. Between 1987 and 1989 we randomly assigned 567 women with small breast cancers (< 2.5 cm in diameter) to quadrantectomy followed by radiotherapy or to quadrantectomy without radiotherapy. All patients underwent total axillary dissection. The median follow-up period was 39 months (range, 28 to 54). RESULTS: The incidence of local recurrence was 8.8 percent among the patients treated with quadrantectomy without radiotherapy, as compared with 0.3 percent among those treated with postsurgical radiotherapy (P = 0.001). However, there was a substantial effect of age: patients more than 55 years old who did not receive radiotherapy had a low rate of local recurrence (3.8 percent). The four-year overall survival was similar in the two treatment groups. CONCLUSIONS: Administering radiotherapy after quadrantectomy reduces the risk of local recurrence in women with small cancers of the breast, but radiotherapy may not be necessary in elderly women.

Breast Neoplasms↗
PubMed1993

Hepatitis C infection in children and adolescents on haemodialysis and after renal transplant.

Serum antibodies to hepatitis C virus (HCV) were measured in children and adolescents on haemodialysis (HD, n = 20) and after renal transplant (RT, n = 33). Seropositivity was observed in 3 HD patients (15%) and in 7 RT patients (21.2%) with an enzyme-linked immunosorbent assay (2nd generation) and a recombinant immunoblotting assay (2nd generation). HCV RNA was detected by the polymerase chain reaction in the 10 patients with anti-HCV antibodies. Anti-HCV positivity was significantly correlated (P < 0.05) with the number of blood transfusions and the time on HD. Transaminase levels were not useful for screening. This study confirms that there is a high risk of HCV infection in children and adolescents on HD or after RT. Moreover, HCV infection is closely related to the number of blood transfusions as well as the time on HD.

Adolescent↗
PubMed1993

Sexual practices and attitudes of street youth in Belo Horizonte, Brazil. Street Youth Study Group.

Street youth are at risk of HIV infection worldwide. To develop effective prevention strategies, information about the meanings and functions of sexual activity for street youth is needed. In this paper, data from structured questionnaires, focus group discussions, in-depth interviews and field observations are used to build up a picture of the sexual culture of 9-to-18-year-olds living and/or working on the streets of a large Brazilian city. The findings reveal that these children and adolescents engage in sexual behavior that puts them at risk of sexually transmitted diseases, including HIV/AIDS, and reinforce that sex is a multi-determined and entrenched behavior in this population. Interventions must take into account the fact that for street youth, sex is used as a means of ensuring survival, seeking comfort, finding pleasure, and dealing with psychological issues that arise during adolescence.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Central small size breast cancer: how to overcome the problem of nipple and areola involvement.

For centrally located small tumours we have sought, with the aid of a plastic surgeon, to achieve the same radicality as in the other quadrants, while achieving a good cosmetic result. We considered 37 patients with small centrally located breast carcinoma, in whom we performed a new surgical technique. From analysis of this series it emerged that a high percentage (54.1%) had nipple and areolar involvement, suggesting their removal; it is no problem to sacrifice these when a good cosmetic result can be achieved by plastic remodelling.

Adult↗
PubMed1993

[Microcalcifications in non-palpable breast carcinoma. Analysis of 427 cases].

Of 836 nonpalpable breast lesions histologically assessed between 1985 and 1991 at the Milan Cancer Institute, 427 were malignant (51%). Microcalcifications were present in 283 tumors (66%), alone in 200 cases or associated with a mass (72 cases) or within a focal distortion (11 cases). Several mammographic, clinical and histological features were analyzed, comparing the 283 lesions with microcalcifications with the 144 tumors represented only by nodular opacities or distortions. This was done to assess the existence of morphologic and prognostic characters differentiating the two subsets and to investigate the reliability of mammography in estimating lesion size. On the average, in our series of cases, the patients with microcalcifications were younger, had a higher rate of dense breasts and a large number of partially or totally intraductal carcinomas. In situ carcinomas were frequent and minimal lesions (< 5 mm) accounted for 43% of the whole at pathologic examination. However, the lesions with microcalcifications were associated with more positive nodes (32% vs 18%). Therefore, microcalcifications, although generally representing an early sign of cancer, appear to suggest a less favorable prognosis.

Adult↗
PubMed1993

Lyme disease in outdoor workers on Assateague Island: high tick-exposure but low disease risk.

Lyme disease is endemic to the Assateague Island area. Using a questionnaire and serosurvey, we examined the extent of tick exposure, compliance with recommended Lyme disease personal preventive activities, and risk of the disease in 86 outdoor workers on Assateague Island before and after the summer of 1989. Despite high self-reported tick exposure and relatively long employment durations on the island, there was no evidence of current or past infection with Borrelia burgdorferi, the causative agent of Lyme disease. Lyme disease knowledge and use of several personal strategies were high, but compliance with these preventive strategies was not universal. These data suggest that even in this high-risk population, intensive educational efforts are necessary to encourage Lyme disease preventive behavior, but the current level of compliance may have decreased the risk of Lyme disease on the island.

Adult↗
PubMed1992

Distribution, density, and Lyme disease spirochete infection in Ixodes dammini (Acari: Ixodidae) on white-tailed deer in Maryland.

A Statewide survey of ticks parasitizing white-tailed deer was carried out in Maryland during November 1989 to assess the status of the deer tick, Ixodes dammini Spielman, Clifford, Piesman & Corwin, the major vector of Lyme disease in the northeastern United States. Ticks were collected from deer carcasses brought in by hunters at 23 check stations (one per county). A total of 3,437 I. dammini were collected from 538 of 1,281 deer (42%), together with 2,013 Dermacentor albipictus (Packard) and 23 Amblyomma americanum (L.) from 34 and 0.5% of deer respectively. I. dammini prevalence ranged from 0 to 79% of deer and mean abundance from 0 to 7.3 ticks per deer at different check stations. Lyme spirochete, Borrelia burgdorferi Johnson, Schmid, Hyde, Steigerwalt & Brenner, infection rates in ticks ranged from 0 to 21%, with a mean of 8%. Deer-tick density and spirochete infection rates varied with physiographic region and were low in the Appalachian, intermediate in the Piedmont, and high in the Western and Eastern Coastal Plains regions. County-based human case rates correlated positively with I. dammini abundance. We concluded that I. dammini was well established except in the mountainous western region of Maryland and was involved in Lyme disease transmission.

Animals↗
PubMed1992

Locally recurrent breast cancer after 'radical' surgery.

Tumor recurrence at the site of radical surgery for mammary carcinoma has been studied in 101 cases. Analysis revealed the proximate causes--tumour size, axillary node metastases--and the more extensive type of surgery have a positive correlation even if the P values do not reach the significant value. The prognosis suggests that clinically this phenomenon, seen in the long term, does not differ from that of distant skin and subcutaneous metastases. A treatment strategy is proposed.

Adult↗