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Biomedical subjects

R Carraro

Publications and source records attributed to R Carraro.

At least 19 recordsLinked to original sources
PubMed2006

Relationship of serum leptin concentration with age, gender, and biomedical parameters in healthy, non-obese subjects.

It is known that the circulating levels of leptin, the adipocyte hormone implicated in the control of energy balance, are correlated with fat body mass (FBM), although the influences of other physiological conditions are not fully understood. We investigated the relationships of serum leptin concentration with age, gender, and 36 hormone-metabolic parameters in a sample of a well defined healthy population (n=246; age range 20-93 years), and in subgroups of lean individuals according to their body mass index (BMI), within similar age range and gender distribution. Only insulin secretion (positively) and testosteronemia (negatively, in males) show direct correlations. The other relationships are not significant but throughout collaborating variables, such as serum lipids, especially through FBM, lean body mass (LBM) through insulin secretion, and gender through FBM. In males, LBM correlates with insulin secretions, s-IGF-1 and with s-testosterone. The relationship between insulin secretion and LBM persists up to advanced age. From the present study it may be concluded that the positive relationship of leptin with insulin secretion and the negative one with testosterone, indicate direct implications of leptin in insulin signaling, as well as in male sexual development. Finally, the fact that the amount of secreted insulin depends on LBM and the latter on testosterone and IGF-1, indicates the importance of muscle mass in the control of insulin secretion.

Adipose Tissue↗
PubMed2003

Role of prevention in the contention of the obesity epidemic.

Obesity has become one of the major health burdens of the westernized world with an increasing number of people affected at any age. Although genetic factors explain around 40% of individual susceptibility to the disease, obesity may and should be controlled through interventions on the individual behaviour and on the social environment. Very promising to this aim is the role of prevention. Several levels of action have been established as well as different types of interventions according to the targeted population. Of special importance is the contention of childhood obesity with home and school as privileged settings for intervention. Despite a general acknowledging of the urgency for effective preventive measures at social, economic and political level to contrast the increasing prevalence of obesity, no clear nationwide policies have yet been established, and the educational and public health measures adopted so far lack that coordination and integration that the magnitude of the situation requires.

Adult↗
PubMed2003

When the ICU patient refuses vital supports.

The aim of this paper is to discuss the problem of caring for ICU patients who request forgoing of intensive supports; in particular, evaluating their competence and building effective relationships among the patients themselves, their relatives and the health care team. The histories of 2 adult competent ICU patients 2 asked that vital intervention be forgone are presented, together with the discussion of problems posed by such a request and of possible solutions which respect patients' autonomy and bystanders needs. These patients were hospitalized in an Italian general 14 bed ICU. The patients' request were weighted against their prognosis and their view of life, in order to evaluate their reliability. Also the refusal of either treatment or outcome was evaluated, in order to effectively safeguard the patients' interests. The request of one patient was satisfied and he was allowed to die, after all the involved people had understood and accepted the final decision. The second patient, who was somehow forced to undergo intensive treatment, is alive and satisfied with having been cured. In Italy too, autonomy is an increasingly applied principle in end-of-life decisions in ICUs. It is usually tempered by a consideration about the patients' best interest as perceived by involved bystanders.

Cardiopulmonary Resuscitation↗
PubMed2003

L-calcium channel blockade induced by diltiazem inhibits proliferation, migration and F-actin membrane rearrangements in human vascular smooth muscle cells stimulated with insulin and IGF-1.

During the atheroma plaque formation, smooth muscle cells (SMC) have to change their differentiated phenotype in order to proliferate, migrate and synthesize collagen. These phenotypic changes are stimulated by insulin and IGF-1, and we have studied the effect of L-type calcium channel blockade produced by diltiazem on such changes. Mitotic activity was measured using bromodeoxyuridine DNA incorporation, the migration capability as chemotaxis index in a Boyden chamber, and cytoskeleton changes related to SMC movement in immunofluorescence studies. Diltiazem (10(-7)-10(-6) M) reduced insulin-induced mitotic activity in cultured human vascular SMC more effectively than in IGF-1-induced mitotic activity, but at 10(-5) M, the inhibitory effects were similar. Diltiazem also showed a clear inhibition of migration ability, both under basal conditions (p < 0.05) and after addition of insulin (p = 0.0001) and IGF-1 (p < 0.0001). Finally, diltiazem inhibited membrane ruffling induced both by insulin and IGF-1 in a similar manner, and similar results were obtained with SMC from rat aorta. We conclude that substances blocking the L-type calcium channels such as diltiazem, could inhibit those processes which in vivo lead SMC to form the atheroma plaque.

Actins↗
PubMed2002

Principles, protocols and patients: the practical management of a limit in ICU.

The definition and management of a limit is a common but sometimes extremely complex problem in the Intensive Care Unit (ICU). Guidelines and consensus documents have been published in order to help clinicians. Yet, many controversial issues are brought into question. Legal rules are sometimes vague and derive more from the interpretation of various and unrelated principles (which vary from country to country) than from a clear ad hoc law. In this sense, the practical management of a limit in ICU is usually run by a dual normativity: an external one, which derives from the cultural, moral and legal values of the society, and an internal one, which depends on the particular clinical and human situation, namely the values of everybody involved in (the patient, his/her relatives, the health staff) and the relationships among these people. The considerable freedom left for the decision by an open communication is a great and favourable potential which must be used in the interest of the patient's and of his/her family.

Clinical Protocols↗
PubMed2000

Bioethical issues related to continuous renal replacement therapy in intensive care patients.

OBJECTIVE: To examine the ethical approach of intensivists and nephrologists to continuous renal replacement therapy (CRRT). DESIGN: A questionnaire. SETTING: The First International Course on Critical Care Nephrology. PARTICIPANTS: The participants in the course (around 500). RESULTS: Most participants think that establishing ethical criteria for managing CRRT is a medical task, as clinicians have adequate criteria for defining futility. However, many responders would grant the request of starting futile CRRT or would maintain it if requested by the family. Only 55% believe that informed consent is necessary for initiating CRRT; one out of four would start or maintain unwanted life-saving CRRT. In case of lack of equipment, the majority would select the patients, excluding the worst one or on a "first-come, first-served" basis. Withholding and withdrawing are regarded differently by most responders. Again, most think that every vital support should be withdrawn when futile, but practical and psychological aspects still influence the final decision. Responders think that ethics critical care committees can help in the management of ethical problems in ICU. CONCLUSIONS: Our results show that several ethical questions are still unsolved and that practical and psychological aspects of the treatment process can be stronger than bioethical principles.

Attitude of Health Personnel↗
PubMed1998

Adipocyte differentiation factor (ADF): a protein secreted by mature fat cells that induces preadipocyte differentiation in culture.

A factor that is released into the culture medium of mature adipocytes and promotes the differentiation (adipogenic conversion) of preadipocytes has been partially characterized. The factor acts in a dose-dependent manner on preadipocytes to produce up to a four-fold increase in triacylglycerol (triglyceride) content and a nine-fold increase in glycerol-3-phosphate dehydrogenase (GPDH) activity, a marker of the late phase of differentiation of preadipocytes. The material appears to be a protein, since it has a molecular weight (Superose-12 gel exclusion chromatography) of about 53 kDa, an isoelectric point (pl) of 4.7-4.9, and is inactivated by the proteases papain and chymotrypsin and extremes of pH (2 and 12). Considerations of molecular weight, isoelectric point, stability to specific proteases, and especially to the action of chemical agents [the adipogenic activity is not affected by either an oxidizing (KIO4) or a reducing agent (DTT)], lead to the conclusion that the differentiation factor is distinct from known cytokines. The authors suggest that the protein be designated adipocyte differentiation factor (ADF). ADF in vivo may act as a cytokine paracrine agent to regulate the differentiation of preadipocytes.

3T3 Cells↗
PubMed1995

RFLP analysis of human chromosome 11 region q13 in multiple symmetric lipomatosis and multiple endocrine neoplasia type 1-associated lipomas.

Six lipomas from patients affected by Multiple Symmetric Lipomatosis (MSL) and by Multiple Endocrine Neoplasia Type 1 (MEN 1) were analyzed for loss of heterozygosity on chromosome 11 region q12-13 using four RFLPs. Allelic loss for the D11S146 locus was found only in one visceral MEN 1-associated lipoma. Lipomas that exhibited a lack of allelic lesions were analyzed for an eventual abnormal amount or a defective function of the Gs protein by studying the Gs alpha subunit gene, codons 201 and 207, by PCR and TGGE techniques. All the samples were negative for activating mutations.

Alleles↗
PubMed1994

Catecholamine-sensitive lipolysis in the rat: different loci for effect of age on the lipolytic cascade in epididymal vs perirenal fat cells.

The biochemical locus of the decrease of lipolytic responsiveness to catecholamines in the aging rat has not heretofore been completely identified. Although increased sensitivity to the inhibitory action of adenosine is the likely explanation for the decrease during maturation, the nature of the age effect during senescence has been unclear. In order to determine whether the proximal or distal portion of the lipolytic pathway is involved, we have studied the lipolytic effect of the distally acting cyclic AMP analogue, 8-(4-chlorophenylthioadenosine)3'5'-monophosphate (cyclic) (Cl-cAMP) on rat fat cells from both the epididymal and perirenal fat pads of mature (6 mo) and senescent (24 mo) Fischer 344 rats. Using an adenosine (N6-1-2-phenylisopropyl-adenosine; PIA) regulated system, the lipolytic response to epinephrine (glycerol release) was measured simultaneously with that to Cl-cAMP. The effects of age on lipolysis are greatly influenced by the anatomic site of origin of the fat cells. The epididymal cells of the old rats showed no decreased responsiveness to either epinephrine or Cl-cAMP. However, the perirenal cells of the old rats showed a grossly impaired maximal response to both epinephrine (60% decrease relative to young; p < .005) and Cl-cAMP (42% and 58% decrease in 2 sets of experiments; p < .05 and .04, respectively). Although decreased lipolytic response to epinephrine in epididymal cells was not seen in these studies, this has been clearly shown in earlier work, suggesting that diminished response to epinephrine is demonstrable only when the system is not already maximally inhibited by PIA.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Deaminase↗
PubMed1993

Omental and epigastric adipose tissue lipolytic activity in human obesity. Effect of abdominal fat distribution and relationship with hyperinsulinemia.

It has been shown that visceral obesity is associated with an increased incidence of hyperinsulinemia. In such a condition, hyperinsulinemia could be due to an increased lipolytic activity of omental adipose tissue (AT), through an enhanced portal flux of FFA. The purpose of our study was to evaluate the lipolytic activity of omental and epigastric AT obtained from morbid obese patients either with prevalently visceral or subcutaneous abdominal fat accumulation, evaluated by computerized tomography. The relationship between plasma insulin values and in vitro lipolytic activity in both tissues was studied. Thirteen visceral (VO) and 13 subcutaneous (SO) obese patients, matched for sex and body mass index, undergoing vertical banded gastroplasty, were studied. Before surgery, in each patient an OGTT was performed. During surgery, samples of epigastric subcutaneous and omental AT were obtained for evaluation of fat cell weight (FCW) and basal, noradrenaline 10(-5)M and isoprenaline 10(-5) M induced lipolytic activities. No significant differences in basal lipolysis were found between the two types of obesity, both in omental and in epigastric AT. In omental AT, a higher noradrenaline and isoprenaline induced lipolysis was observed in VO than in SO. Isoprenaline induced lipolysis of omental AT (expressed per cell surface area) correlated directly with FCW. VO patients showed plasma insulin values after OGTT significantly higher than SO patients. In the whole group of patients, independently from fat distribution, significant correlations were found between the incremental areas of the plasma insulin curve during OGTT and the noradrenaline an isoprenaline induced lipolytic activities both in omental and epigastric adipose tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Abdomen↗
PubMed1993

Body composition study in the elderly: comparison between tritium dilution method and dual photon absorptiometry.

BACKGROUND: The methods commonly employed in body composition study in elderly persons derive fat-free mass (FFM) by measures of total body water (TBW); these methods assume FFM hydration constant (TBW/FFM = 0.732). The aim of our study was to verify the accuracy of the TBW method in FFM estimation and to study the variability of fat-free mass hydration (TBW/FFM) in healthy elderly subjects. METHODS: We assessed FFM in 27 healthy old subjects (76 +/- 7 yrs) by dual photon absorptiometry (DPA) and by TBW measured by 3H2O. Furthermore, to verify the accuracy in FFM estimation by our methods, we measured resting metabolic rate (RMR) by indirect calorimetry. RESULTS: FFM hydration was 71.9 +/- 4.9 (range 63.6-80.4%), a range larger than that reported by direct chemical analysis in adults. The FFM hydration measured in our subjects was not different from the 73.2 value currently used in healthy adults. FFM values derived by TBW (assuming TBW/FFM = 0.732) were not significantly different from FFM measured by DPA. We correlated FFM with resting metabolic rate and found a similar correlation between RMR and FFM-DPA (r = .89, p < .001) and FFM-TBW (r = .85, p < .001). CONCLUSIONS: Both methods employed in our study have proved to be accurate in estimating FFM in elderly persons; particularly, the value of 0.732 assigned to FFM hydration to derive fat-free mass in adults can be employed also in body composition study of the elderly.

Absorptiometry, Photon↗
PubMed1992

Adipocytes of old rats produce a decreased amount of differentiation factor for preadipocytes derived from adipose tissue islets.

Adipose tissue of young rats (3.5 mo) contains cell formations ("islets") that, in culture, give rise to a variety of preadipocytes, or islet-derived cells (IDCs), that undergo rapid morphologic differentiation into adipocytes. Such adipose conversion depends on a differentiation-promoting factor produced by the mature adipocytes also present in the cultures. Here we report that cultured IDCs from epididymal fat of senescent rats (20 +/- 3 mo) show decreased adipose conversion compared to IDCs from 3.5 mo rats at 3 days of culture (14.2% vs 29.9%; p < .001). Both the number of co-cultured adipocytes and increased fragility with age were excluded as having a substantial role in explaining the decreased conversion. In order to determine whether the decrease differentiation of the IDCs of the old rats was intrinsic or due to reduced production of the differentiation factor by the old adipocytes, cross-over cultures of IDCs from young and old rats were grown in the presence of young or old adipocytes. When IDCs of old rats were cultured in the presence of young adipocytes, a significant twofold increase in differentiation was seen compared to old IDCs grown with old adipocytes (22.7% vs 10.3%; p < .001). This response was comparable to that of young IDCs grown with young adipocytes. Thus, old IDCs retain their ability to undergo extensive morphologic differentiation when appropriately stimulated. Reduced production of the differentiation-promoting factor by old adipocytes rather than the ability of IDCs to differentiate appears to be responsible for the decreased adipose conversion of IDCs seen in cultures of adipose tissue from senescent rats.

Adipose Tissue↗
PubMed1992

Lipoprotein sub-fraction levels and composition in obese subjects before and after gastroplasty.

Obesity is frequently associated with several alterations of plasma lipid levels and lipoprotein metabolism. To evaluate the effects of severe obesity and weight loss on plasma lipoprotein sub-class levels and composition 11 grossly obese patients were examined before and six and 12 months after gastroplasty. Plasma lipoproteins were isolated by ultracentrifugation in a zonal rotor under rate flotation conditions. Mean body weight was 121.9 kg before gastroplasty, 97.6 kg after six months, and 90.7 kg after 12 months. Total plasma cholesterol was not affected by the weight reduction. Obese patients were characterized by increased levels of IDL and small dense LDL (LDL3). LDL levels, but not LDL3, were reduced following weight reduction. Plasma apo B levels of obese patients were always higher than in controls and were not affected by the weight reduction. After 12 month's weight loss total HDL cholesterol increased without modification of HDL sub-class cholesterol distribution, which was similar to that of normal controls. Plasma apo AI in obese patients was not affected by changes in body weight, and remained below normal. The percentage protein-lipid composition of LDL2 and HDL3 in obese patients was characterized by a decreased cholesterol ester content before gastroplasty which was normalized 12 months after gastroplasty. The presence of IDL and LDL3 in increased concentrations in severely obese patients may represent a vascular risk factor since similar abnormalities were recently observed in non-obese patients affected with vascular diseases.

Adult↗
PubMed1992

Assessment of abdominal fat distribution in obese patients: anthropometry versus computerized tomography.

The accuracy of waist to hip girth ratio (WHR) in assessing visceral/subcutaneous abdominal fat distribution has not yet been clearly established in the obese population. The purpose of the present study was to evaluate the relationship between WHR and visceral/subcutaneous fat distribution, both assessed by computerized tomography (CT), in a group of 28 obese patients (15 male, 13 female). Furthermore, 33 normal weight or slightly overweight subjects (23 male, 10 female) were studied as a control group. Obese subjects of both sexes were found to have higher values of WHR than non-obese; conversely visceral:subcutaneous fat area ratio (VSR) values did not differ significantly. Significant correlation between WHR and BMI was present both in males (r = 0.41, P < 0.01) and in females (r = 0.54, P < 0.01). In normal weight males significant correlations between WHR and visceral fat area or VSR were found. In obese males these correlations were much weaker. In normal weight females a significant correlation was found between waist circumference and visceral fat area, whereas in obese females no positive correlations were found between anthropometric measurements and CT indices of visceral fat distribution. In conclusion, WHR cannot be considered as a reliable index of visceral/subcutaneous fat distribution in obese patients, particularly if they are females.

Abdomen↗
PubMed1991

Islets of preadipocytes highly committed to differentiation in cultures of adherent rat adipocytes. Light- and electron-microscopic observations.

Cultures of adherent mature adipocytes, obtained from collagenase-digests of adipose tissue of the rat, invariably contain rapidly proliferating, fibroblast-like cells despite the washing and centrifugation procedures employed during isolation of the fat cells. Such spindle-like cells originate from low-density structures, which we term "islets", that are present, together with the mature adipocytes, in the floating layer of the digest of adipose tissue. Islets are found in preparations from adult (3-4 months old) as well as aging (17-24 months old) rats. By light- and electron microscopy, the islets appear as clusters of closely associated cells containing a variable amount of lipid-like material. Cells of endothelial or pericytic origin are also present in the islets. Within a few hours of culture, the islets give rise to those spindle-like cells that have been seen to proliferate in the cultures. By 36-48 hours, such cells begin to accumulate lipid droplets and, by 150 hours, assume the morphology of small mature adipocytes (diameter 20-35 microns) with a large central lipid droplet. The pattern of differentiation of these cells recalls that of preadipocytes derived from the stromal-vascular fraction of adipose tissue digests. Nonetheless, the extent and rapidity of their adipose conversion, as well as the culture conditions necessary for differentiation, are different and suggest that these cells are a substantially uniform subpopulation of adipocyte-precursor cells highly committed to differentiation.

Adipose Tissue↗