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Biomedical subjects

R Pacifici

Publications and source records attributed to R Pacifici.

At least 73 records · Page 4Linked to original sources
PubMed1997

Hair analysis for nicotine and cotinine: evaluation of extraction procedures, hair treatments, and development of reference material.

Analysis of nicotine and cotinine in human hair can provide information on nicotine intake and exposure to environmental tobacco smoke over a long period of time. Nonetheless, to better assess the usefulness of hair analysis to determine smoking habits or exposures, all procedures have to be standardized. Various solvents were tested as washing solvents to eliminate external contamination from nicotine. Dichloromethane was found effective when used for two washes prior to the extraction. Basic and acid digestion of hair followed by solid phase extraction with Extrelut-3 glass column using dichloromethane:isopropyl alcohol (9:1) as eluting mixture both gave good recoveries of nicotine and cotinine, when compared with extractions reported in the literature. The extraction method was free from substances, which could interfere in the chromatographic analysis. Furthermore, the addition of methanolic HCl to the eluting mixture prevented the loss of nicotine during the evaporation step before chromatography. Chromatography was performed using a reversed-phase column and a U.V. detection at 254 nm. Furthermore, hair treatments (dyes, permanent wave, hydrogen peroxide) caused a major decrease in the nicotine content in hair, and a smaller effect on cotinine levels. However, the effect of various treatments was not reproducible. Several attempts to produce reference materials were carried out. Nicotine and cotinine standard solutions at different concentrations were added to blank hair soaked in dimethylsulfoxide, methanol and water.

Chromatography, High Pressure Liquid↗
PubMed1997

The analysis of nicotine in infants' hair for measuring exposure to environmental tobacco smoke.

Hair samples were collected from 24 infants (3-36 months) exposed and non-exposed to environmental tobacco smoke. Hair was washed in dichloromethane, digested in NaOH, extracted by solid-phase extraction and analyzed by high-performance liquid chromatography to determine the content of nicotine and cotinine. Nicotine concentration in non-exposed infants (1.3 +/- 1.7 ng/mg hair) was significantly different from that in occasionally exposed infants (6.8 +/- 2.1 ng/mg hair) and that in infants passively exposed to smoke (15.4 +/- 6.7 ng/mg hair). Cotinine could be measured only in passive smokers infants. These findings suggest the possibility of monitoring exposure to environmental tobacco smoke in infants by using nicotine measurement in hair rather than in urine, blood or saliva.

Biomarkers↗
PubMed1997

Age-related cortical bone loss at the metacarpal.

In order to evaluate in vivo the entity of endosteal and periosteal changes with age in the two sexes, and their relative contribution to age-related cortical bone loss, we undertook a cross-sectional study on a population of normal Caucasian subjects. The group included 189 women and 107 men who were studied by photodensitometry and radiogrammetry of the second metacarpal bone, derived from the same standard hand X-ray. Of the subjects, 134 were 65 years of age or older (75 women and 59 men). Metacarpal bone mineral density (BMD) correlated with age in both sexes, with an annual bone loss rate of 0.5% in women and 0.15% in men. In the over 65 group, correlation was significant only in women, who underwent an acceleration in the rate of bone loss (1% per year). Marrow cavity width (M), cortical index at the second metacarpal shaft (MI) and external width (W) all correlated with age in both sexes, although generally better in the female than in the male sex. M almost doubled from the fourth to the ninth decade in women and increased 50% in men. In the same age interval, MI showed an annual decrease of 0.49% in females and 0.33% in males. In the over 65 group, cortical thinning rate was significant in women (0.39% per annum) but not in men (0.14% per annum), whereas correlation of W was not significant in either sex. Finally, MI correlated with BMD in the whole study population and in the over 65, with a female prevalence in correlation strength maintained throughout life. The following conclusions can be derived for metacarpal aging: (1) an acceleration in cortical bone loss occurs in females after age 65; (2) age-related growth in periosteal diameter, although significant in the whole population, is negligible in the elderly of both sexes; (3) age-related cortical bone loss is generally more dependent on cortical thinning in women than in men.

Adult↗
PubMed1997

Cytokine production in saquinavir treated mice.

The effects of chronic and acute saquinavir treatment on murine cytokine production were investigated in both plasma and splenocyte cultures. Cytokine plasma levels were below the detection limit in both saquinavir treated mice and in control mice with the exception of IFN-gamma, whose levels were detectable in 15 day treated mice. Saquinavir was found to increase interferon gamma (IFN-gamma) and interleukin-2 (IL-2) production from stimulated splenocytes. Saquinavir also caused a marked reduction of transforming growth factor-beta 1 (TGF-beta 1) in supernatants of splenocytes cultures. Conversely, interleukin-1 beta (IL-1 beta), interleukin-10 (IL-10) and tumor necrosis factor-alpha (TNF-alpha) production was not modified by drug treatment. In the present paper we hypothesized that this protease inhibitor may be involved in the immunoregulatory cytokine network.

Animals↗
PubMed1997

Zinc supplementation and plasma lipid peroxides in an elderly population.

OBJECTIVE: To determine the effect of vitamin A, zinc or both on plasma lipid peroxides in a healthy elderly population. DESIGN: Double-blind randomized controlled trial supplementation of vitamin A and zinc. SETTING: Public home for elderly people, in Rome, Italy. SUBJECTS: A total of 178 residents of a Public home for elderly people were evaluated regarding health and nutritional status. 136 gave a written consensus to participate in the trial and were randomized in four groups of treatment. 118 elderly completed the trial. INTERVENTIONS: Three months supplementation of the following treatments: (1) vitamin A (800 micrograms retinol palmitate); (2) zinc (25 mg zinc as sulphate); (3) vitamin A and zinc (800 micrograms retinol palmitate and 25 mg zinc as sulphate); (4) placebo (starch containing capsules). MAIN OUTCOME MEASURES: Plasma lipid peroxides (TBA-RS) were measured before and after supplementation. RESULTS: Zinc supplementation was associated with a decrease in plasma lipid peroxides (beta = -0.19; 95% confidence levels: -0.37, -0.002; p-value = 0.05) after adjusting for sex, smoking habits, baseline plasma lipid peroxides and vitamin A plasma levels. CONCLUSIONS: Zinc supplementation decreased plasma lipid peroxides while vitamin A had no effect in this elderly population. Adequate zinc intake or supplementation could play an important role in the prevention and/ or modulation of diseases in the elderly people.

Aged↗
PubMed1997

The in-vitro effects of nicotine and cotinine on sperm motility.

Swim-up spermatozoa from the seminal samples of non-smokers, usually not exposed to passive smoking, were treated in vitro with nicotine (NIC) and cotinine (COT) at the average levels found in smokers' seminal plasma and at levels 500 times higher than this average. This was done to evaluate the action of these drugs on sperm motility. Each sample was allowed to swim up in Tyrode's solution with or without the drug; the study was carried out at time 0 and +1, +2, +4, +8 and +24 h of incubation, using a light microscope and a CASA system (experiment 1). In addition, the direct action of smoke on spermatozoa was studied using aspirated cigarette smoke (experiment 2). Kinetic parameters were then measured at 30 min, 45 min and 60 min starting from the last smoke injection. The first experiment showed that NIC and COT at average levels did not produce statistically significant variations of the kinetic parameters studied up to 24 h. However, the much higher concentration significantly altered all the kinetic variables in relation to the time of incubation. The second experiment with smoke in toto demonstrated a sharp reduction in all the sperm kinetic parameters. This reduction was seen after 30 min exposure to smoke and increased progressively until almost complete immotility at 1 h of exposure. These results suggest that NIC and COT are not responsible for the harmful effects of cigarette smoke on sperm kinetic parameters reported in the literature.

Adult↗
PubMed1997

The functional block of TNF but not of IL-6 prevents bone loss in ovariectomized mice.

Considerable evidence supports the hypothesis that estrogen prevents bone loss by blocking the bone marrow cell production of pro-osteoclastogenic cytokines. However, controversy remains on the role of candidate factors, such as tumor necrosis factor (TNF) and interleukin-6 (IL-6). To investigate the contribution of these cytokines to the pathogenesis of ovariectomy (OVX)-induced bone loss, OVX mice were treated with either TNF binding protein (TNFbp), an inhibitor of TNF, the anti-(IL-6) antibody (Ab) 20F3, or estrogen for the first 2 weeks after surgery. OVX caused a rapid decrease in trabecular bone volume (TBV) and an increase in in vivo bone resorption, as assessed by bone histomorphometry. Treatment with TNFbp completely prevented bone loss and the increase in both osteoclast formation and bone resorption induced by OVX, but had no effects in sham-operated controls. In contrast, treatment with anti-IL-6 antibody failed to prevent bone loss, and the increase in bone resorption and osteoclastogenesis induced by OVX. These data demonstrate that in nongenetically manipulated mice, the estrogen-regulated cytokine that plays a central role in the mechanism by which estrogen deficiency causes bone loss is not IL-6, but rather TNF.

Animals↗
PubMed1996

Estrogen deficiency increases the ability of stromal cells to support murine osteoclastogenesis via an interleukin-1and tumor necrosis factor-mediated stimulation of macrophage colony-stimulating factor production.

To analyze how estrogen blocks osteoclastogenesis, we investigated the effects of ovariectomy on osteoclast (OC) formation in co-cultures of purified OC precursors and purified stromal cells (SC). OC formation was higher in co-cultures containing SC from ovariectomized mice than in those containing SC from sham-operated mice, thus suggesting that estrogen regulates osteoclastogenesis by targeting SC. Ovariectomy also increased the mononuclear cell secretion of interleukin (IL)-1) and tumor necrosis factor (TNF) and the SC production of macrophage colony-stimulating factor (MCSF). Osteoclastogenesis and SC production of M-CSF were not blocked by in vitro estrogen treatment but were decreased by in vivo treatment of donor mice with either estrogen or a combination of the IL-1 inhibitor, IL-1 receptor antagonist, and the TNF inhibitor, TNF binding protein. IL-1 and TNF production were also blocked by in vivo estrogen treatment, demonstrating that the increased bone marrow levels of IL-1 and TNF characteristic of ovariectomized mice induce the formation of a SC population characterized by a high production of M-CSF and increased pro-osteoclastogenic activity. Since in co-cultures of SC and OC precursors M-CSF levels correlated with OC production (r = 0.7, p < 0.0001), the data also indicate that the pro-osteoclastogenic activity of SC is proportional to their secretion of M-CSF. The ability of estrogen to decrease SC production of M-CSF and the pro-osteoclastogenic activity of these cells by regulating IL-1 and TNF production is a previously undescribed mechanism by which estrogen down-regulates osteoclastogenesis.

Animals↗
PubMed1996

Human blood-mobilized hematopoietic precursors differentiate into osteoclasts in the absence of stromal cells.

Osteoclastogenesis is a complex process that is facilitated by bone marrow stromal cells (SCs). To determine if SCs are an absolute requirement for the differentiation of human hematopoietic precursors into fully mature, osteoclasts (OCs), CD34+ cells were mobilized into the peripheral circulation with granulocyte colony-stimulating factor, harvested by leukapheresis, and purified by magnetic-activated cell sorting. This procedure yields a population of CD34+ cells that does not contain SC precursors, as assessed by the lack of expression of the SC antigen Stro-1, and that differentiates only into hematopoietic cells. We found that CD34+, Stro-1- cells cultured with a combination of granulocyte/macrophage colony-stimulating factor, interleukin 1, and interleukin 3 generated cells that fulfill current criteria for the characterization of OCs, including multinucleation, presence of tartrate-resistant acid phosphatase, and expression of the calcitonin and vitronectin receptors and of pp60c-src tyrosine kinase. These OCs also expressed mRNA for the noninserted isoform of the calcitonin receptor and excavated characteristic resorption pits in devitalized bone slices. These data demonstrate that accessory SCs are not essential for human osteoclastogenesis and that granulocyte colony-stimulating factor treatment mobilizes OC precursors into the peripheral circulation.

Acid Phosphatase↗
PubMed1996

ErbB receptor activation, cell morphology changes, and apoptosis induced by anti-Her2 monoclonal antibodies.

A panel of mAbs were generated against the purified soluble form of erbB2/Her2 receptor, corresponding to the extracellular region of the receptor, and examined for their ability to mimic the receptor ligand. Some of the mAbs strongly induced tyrosine phosphorylation of 180-185 kDa proteins, including not only Her2 but also Her3 and Her4 receptors, when they were expressed on the surface of breast cancer cells. These mAbs do not cross-react with Her3 or Her4 as demonstrated by competition study. Receptor phosphorylation was also observed with the cell lines transfected with Her2 or a chimeric receptor consisting of the extracellular domain of Her2 and the transmembrane and cytoplasmic domains of epidermal growth factor receptor. Selected mAbs were tested for their ability to change cell morphology, and one specific mAb, mAb74, induced cell morphology changes and apoptosis.

Animals↗
PubMed1996

Bone quality factor analysis: a new noninvasive technique for the measurement of bone density and bone strength.

The sensitivity of bone mineral density (BMD) as a predictor of fracture risk is limited by the fact that this index does not take into account the geometrical and material characteristics of bone. In contrast, both BMD and bone architecture influence the quality factor (QF), the fraction of the inverse of the energy lost in one cycle of deformation. In this study we have compared the sensitivity of a QF analyzer and dual-energy X-ray absorptiometry (DXA) in detecting the changes induced by ovariectomy (OVX) on the QF, impact strength, and BMD of the femur of mature rats. QF and BMD were measured noninvasively before and 4 weeks after OVX or sham operation using a QF analyzer developed in our laboratory and a Hologic QDR 2000 bone densitometry, respectively. Impact strength was measured in excised femurs at the end of the study. The in vivo short-term precision (coefficient of variation) of the QF analyzer was 1.9%. BMD and QF measurements were highly correlated (r = 0.80,p <0.0001). At baseline, QF and BMD were similar in OVX and sham-operated rats. At 4 weeks, BMD was 14.7 + or - 0.9% lower than at baseline (p < 0.001) in OVX rats and 5.3 + or - 1.3% lower in sham-operated rats (p <0.05). QF decreased 36.0 + or - 2.8% (p <0.0001) in OVX and 10.6 + or - 3.6% in sham rats (p <0.01). As a result, at 4 weeks the difference between sham-operated and OVX rats was larger (p < 0.05) by QF than by BMD. Moreover, QF correlated better than BMD with impact strength and the difference in impact strength between sham and OVX mice was closer to that in QF than that in BMD. These data demonstrate that QF analysis is a precise technique that is more sensitive than DXA in detecting the changes in bone density and strength induced by OVX. QF analysis may represent a new, simple, and economic technique for predicting fracture risk.

Animals↗
PubMed1996

Estrogen, cytokines, and pathogenesis of postmenopausal osteoporosis.

In summary, available data demonstrate that IL-1 and TNF are the causative agents underlying the bone loss induced by estrogen deficiency. Indeed, these factors are produced in bone and the bone marrow, released in larger amounts from cells of estrogen-deficient subjects, and indispensable for reproducing the effects of estrogen deficiency in bone. These observations support the hypothesis that the bone sparing effect of estrogen is due to the ability of the hormone to block osteoclastogenesis, the activation of mature osteoclasts and, as recently demonstrated, the rate of apoptotic osteoclast death. Although IL-1 and TNF play a prominent causal role in these events, the bone-sparing effect of estrogen is mediated by numerous cytokines which, by simultaneously stimulating multiple target cells, induce effects that are not accounted for by any one single factor (Fig. 2). The ability of estrogen to regulate some, but not all, the cytokines involved in this process is not inconsistent with this hypothesis because cytokines have potent synergistic effects. Thus, a considerable increase in bone resorption may result from a relatively small increase in the concentration of only a few of the bone-resorbing factors present in the bone microenvironment. This concept is best illustrated by the study of Miyaura et al. demonstrating that the concentrations of either IL-1, IL-6, IL-6 receptor, or prostaglandins detected in the bone marrow of OVX mice are insufficient to account for the increased bone resorption caused by estrogen withdrawal. In contrast, the increase in bone resorption induced by OVX can be explained by the cumulative effects of these cytokines. Thus, a better understanding of the cooperative effects of cytokines and a recognition that the contribution of individual cytokines to postmenopausal bone loss varies with the passage of time after menopause are necessary to fully understand the mechanism of action of estrogen in bone. Although the relevance of individual bone-targeting cytokines in species specific, the development of transgenic mice with activatable or deactivatable promoters is likely to result in a further clarification of the integrated action of estrogen-regulated cytokines in human bone cells and lay the foundations for the use of cytokine inhibitors in the treatment of postmenopausal osteoporosis.

Animals↗
PubMed1996

Immunological changes among farmers exposed to phenoxy herbicides: preliminary observations.

OBJECTIVES: To evaluate short term immunological changes after agricultural exposure to commercial formulations of chlorophenoxy herbicides. METHODS: Blood samples were collected from 10 farmers within seven days before exposure, one to 12 days after exposure, and again 50 to 70 days after exposure. Whole blood was used to count lymphocyte subsets with monoclonal antibodies. Peripheral blood mononuclear (PBM) cells were used to measure natural killer (NK) cell activity and lymphocyte response to mitogenic stimulations. Values before exposure were used as reference. RESULTS: In comparison with concentrations before exposure, a significant reduction was found one to 12 days after exposure in the following variables (P < 0.05): circulating helper (CD4) and suppressor T cells (CD8), CD8 dim, cytotoxic T lymphocytes (CTL), natural killer cells (NK), and CD8 cells expressing the surface antigens HLA-DR (CD8-DR), and lymphoproliferative response to mitogen stimulations. All immunological values found 50-70 days after exposure were comparable with concentrations before exposure, but mitogenic proliferative responses of lymphocytes were still significantly decreased. CONCLUSIONS: According to our data agricultural exposure to commercial 2,4-dichlorophenoxyacetic acid (2,4-D) and 4-chloro-2-methylphenoxyacetic acid (MCPA) formulations may exert short term immunosuppressive effects. Further studies should clarify whether the immunological changes found may have health implications and can specifically contribute to cancer aetiology.

2,4-Dichlorophenoxyacetic Acid↗
PubMed1996

Lung function in children and adolescents with occasional exposure to environmental tobacco smoke.

We investigated the effects of occasional exposure to environmental tobacco smoke (ETS) on lung function in children. A total of 317 healthy 12- to 15-yr-old nonsmoking children and adolescents, living in households in which none of the adults were active smokers, were selected for the present analysis. The urinary cotinine:creatinine ratio (CCR) was taken as the biologic indicator of exposure, and children were classified according to CCR quartiles. The ratio between FEV1 and FVC (FEV1/FVC) and both early (peak expiratory flow [PEF]) and midexpiratory flow rates (FEF25-75) were lower in children with higher CCR values. In percent terms, the decrease in adjusted lung function for children belonging to the second, third, and fourth quartiles in comparison with those in the first quartile was -1.37, -2.12, and -1.94 for FEV1/FVC (p for trend = 0.012); 0.98, -3.31, and -4.54 for PEF (p for trend = 0.024); and -0.05, -4.85, and -6.13 for FEF25-75 (p for trend = 0.022), respectively. The effects remained significant when possible confounding by father's education and urinary creatinine level had been taken into account, and when children whose parents' smoking status may have been misclassified were excluded. This study suggests an adverse effect on lung function from even low-level exposure to ETS among nonsmoking children living with reportedly nonsmoking parents.

Adolescent↗
PubMed1996

Drug monitoring in nonconventional biological fluids and matrices.

Determination of the concentration of drugs and metabolites in biological fluids or matrices other than blood or urine (most commonly used in laboratory testing) may be of interest in certain areas of drug concentration monitoring. Saliva is the only fluid which can be used successfully as a substitute for blood in therapeutic drug monitoring, while an individual's past history of medication, compliance and drug abuse, can be obtained from drug analysis of the hair or nails. Drug concentrations in the bile and faeces can account for excretion of drugs and metabolites other than by the renal route. Furthermore, it is important that certain matrices (tears, nails, cerebrospinal fluid, bronchial secretions, peritoneal fluid and interstitial fluid) are analysed, as these may reveal the presence of a drug at the site of action; others (fetal blood, amniotic fluid and breast milk) are useful for determining fetal and perinatal exposure to drugs. Finally, drug monitoring in fluids such as cervical mucus and seminal fluid can be associated with morpho-physiological modifications and genotoxic effects. Drug concentration measurement in nonconventional matrices and fluids, although sometimes expensive and difficult to carry out, should therefore be considered for inclusion in studies of the pharmacokinetics and pharmacodynamics of new drugs.

Biological Availability↗