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Biomedical subjects

F Carbone

Publications and source records attributed to F Carbone.

At least 19 recordsLinked to original sources
PubMed2005

Carotid endarterectomy in heart transplant patients.

AIM: The aim of this study was to determine the clinical outcome of carotid endarterectomy in heart transplant recipients and morphologic features of atherosclerotic plaques removed during operation. METHODS: Between April 1993 and October 2001 5 heart transplant patients with symptomatic carotid stenosis >70% underwent carotid endarterectomy with regional anesthesia, including a staged bilateral procedure in one patient. Cholesterol, triglycerides, HDL-cholesterol, LDL-cholesterol were evaluated in each patient. The plaques ( n=6) underwent histologic analysis after carotid endarterectomy. Carotid artery duplex imaging was added to the routine postoperative evaluation. RESULTS: Carotid plaques resulted to be echolucent on B-mode ultrasound examination. Cholesterol, triglycerides and LDL-cholesterol levels were found to be increased, while HDL-cholesterol were decreased. All patients underwent successful carotid endarterectomy; there were no perioperative deaths, major neurologic or cardiac events. The mean length of stay was 2.2 days. The mean follow-up was 44 months. In 1 case, an asymptomatic restenosis >50% occurred 9 months later and, in 2 other cases, a contralateral mild stenosis was found 12 and 36 months later. One patient had a progressive contralateral stenosis, requiring operation 18 months later. High lipid content and heterogeneous cellular infiltration were observed, including macrophages, T-lymphocytes, neutrophils, and also eosinophils in the rapidly progressing plaque. CONCLUSIONS: Heart transplant patients receiving immunosuppression may successfully undergo carotid endarterectomy, without increased risk, but progression of atherosclerotic disease in the carotid arteries seems to continue, despite lipid-lowering regimen and antiplatelet therapy.

Aged↗
PubMed2003

Quantum critical behaviour in a high-T(c) superconductor.

Quantum criticality is associated with a system composed of a nearly infinite number of interacting quantum degrees of freedom at zero temperature, and it implies that the system looks on average the same regardless of the time- and length scale on which it is observed. Electrons on the atomic scale do not exhibit such symmetry, which can only be generated as a collective phenomenon through the interactions between a large number of electrons. In materials with strong electron correlations a quantum phase transition at zero temperature can occur, and a quantum critical state has been predicted, which manifests itself through universal power-law behaviours of the response functions. Candidates have been found both in heavy-fermion systems and in the high-transition temperature (high-T(c)) copper oxide superconductors, but the reality and the physical nature of such a phase transition are still debated. Here we report a universal behaviour that is characteristic of the quantum critical region. We demonstrate that the experimentally measured phase angle agrees precisely with the exponent of the optical conductivity. This points towards a quantum phase transition of an unconventional kind in the high-T(c) superconductors.

Journal Article↗
PubMed2002

Rectal perforations. Personal experience and literature review.

BACKGROUND: Rectal perforation presents high morbidity and mortality and its treatment is still not standardized, it is still rather based on the surgeon's personal experience. This retrospective trial, with a literature review, aims to define these types of lesions, and tries to identify the diagnostic and therapeutic options able to reduce related morbidity and mortality. METHODS: On 1175 operations conducted for colo-rectal emergency, over a ten-year period at our institution, fourteen consecutive patients (1.2%) were seen and treated for rectal perforation. In 43% of cases the treatment consisted in Hartmann's procedure, in the 28.5% ones in rectal wound repair with diverting colostomy and in 28.5% left in diverting colostomy alone. RESULTS: There were no postoperative complications in 86% of patients, and no deaths from sepsis. In 28.5% of cases intestinal continuity was restored at our institution. CONCLUSIONS: Our results demonstrate that a standardized protocol which is based on patients' conditions, type and degree of rectal injury and of peritonitis, must be followed in order to determine the type of surgical option and consequently to reduce the morbidity and mortality related to rectal perforation.

Adolescent↗
PubMed2001

Outpatient management of superficial temporal artery aneurysms.

BACKGROUND: To evaluate the feasibility and safety of surgical treatment of the superficial temporal artery aneurysms on an outpatient basis. METHODS: The records of 5 patients seen at our institution from 1983 to 1997 were reviewed retrospectively. Preoperative diagnosis was made by patient s history and physical examination, with no further evaluation. RESULTS: Outpatient ligation and excision of four aneurysms of distal branches of the superficial temporal artery (3 frontal, 1 parietal) and one involving its proximal portion was performed under local anesthesia. Supplementation with minimal intravenous sedation facilitated the treatment in an uncooperative child and in the patient affected with proximal STA aneurysm. All procedures were uneventful. Patients were discharged a few hours after surgical treatment. No patient required hospitalization following discharge. No recurrence was noted during follow-up periods of 2 to 16 years. CONCLUSIONS: Outpatient diagnosis and excision of aneurysm of the superficial temporal artery can be performed safely. Significant advantages of this pathway include no hospital admission and cost reduction.

Adult↗
PubMed1998

Induction of peripheral CD8+ T-cell tolerance by cross-presentation of self antigens.

There is now convincing evidence that CD8+ T cells can be activated by professional antigen-presenting cells which present antigens derived from non-lymphoid tissues in association with MHC class I molecules in the draining lymph nodes. This mechanism, referred to as cross-presentation, enables the immune system to respond to those microorganisms that infect only non-lymphoid tissues. Consistent with this view, cross-presentation was found to focus on antigens expressed in high concentrations and those released from dying cells, which can be expected to result from viral infections. Recent evidence, however, demonstrates that high dose self antigens can be cross-presented constitutively, resulting in the activation of autoreactive CD8+ T cells. This does not lead to auto immunity under physiologic conditions, but to CD95-mediated deletion of the T cells. Cross-presentation can thus engage a well-defined pathway of antigen-induced T-cell death and purge the immune system of autoreactive CD8+ T cells. Low dose self antigens are not cross-presented and are consequently ignored. The immune system therefore uses two strategies to avoid CD8+ T-cell-mediated autoimmunity in the periphery: deletion of autoreactive CD8+ T cells responding to high dose self antigens and ignorance of self antigens expressed at low concentrations.

Animals↗
PubMed1997

Activation and migration of CD8 T cells in the intestinal mucosa.

The activation of CD8 T cells was studied using transgenic mice expressing an MHC class I-restricted OVA-specific TCR (OT-I). Immunization of OT-I mice resulted in activation of lymph node T cells and up-regulation of expression of B220, CD11a, and CD44 and caused a preferential loss of mucosal-type T cells from the periphery. Immunization induced dramatic changes in intestinal lymphocytes, including the appearance of a CD11a high population that resembled peripheral T cells and induced a primary cytolytic response. Activation of adoptively transferred OT-I cells induced migration of CD8 T cells into the lamina propria and intraepithelial lymphocyte compartments. The results suggest that Ag presentation in the intestinal epithelium occurs, and that CD8 cells activated in the periphery can readily enter the mucosa during an ongoing immune response.

Animals↗
PubMed1997

Comparative evaluation of the E test, agar dilution, and broth microdilution for testing susceptibilities of Helicobacter pylori strains to 20 antimicrobial agents.

The Epsilometer test (E test; AB Biodisk, Solna, Sweden), a new quantitative technique for the determination of antimicrobial susceptibility, was compared to reference methods (agar dilution and broth microdilution) for the antimicrobial susceptibility testing of Helicobacter pylori. Seventy-one H. pylori strains isolated from patients with duodenal ulcers were tested against 20 antimicrobial agents. The E test and the agar dilution method were carried out on Mueller-Hinton agar; the broth microdilution method was performed with Mueller-Hinton broth. The E-test results showed excellent correlation with the agar dilution results, with 91.3 and 98.8% agreement within 1 and 2 log2 dilution steps, respectively, in a total of 1,350 tests. The correlation between the E-test results and the broth microdilution results was slightly higher, with 91.6 and 99.1% agreement within 1 and 2 log2 dilution steps, respectively, in a total of 1,317 tests. There were six major errors and two very major errors by the metronidazole E test compared to the results obtained by reference methods. Excellent agreement between E-test, agar dilution, and broth microdilution results was found for resistance to erythromycin (8%), clarithromycin (6%), and tetracycline (6%). Our results confirm that the E test is comparable to standardized methods for susceptibility testing. Therefore, the E test is a reliable and alternative method for testing H. pylori susceptibility to a wide range of antimicrobial agents in clinical practice.

Anti-Bacterial Agents↗
PubMed1996

Is multiple pregnancy an unavoidable complication of ovulation induction? The case for pulsatile GnRH.

Ovarian hyperstimulation (OHS) and multiple pregnancy are dreaded complications of ovulation induction. The use of pulsatile GnRH permits to prevent the occurrence of OHS and results in few multiple pregnancies. Low-dose GnRH administration, avoidance of preovulatory hCG, patient selection, and the use of GnRH agonist pituitary desensitization in selected patients permits to limit multiple conceptions to a level comparable with the occurrence of this complication in normal unstimulated women.

Chorionic Gonadotropin↗
PubMed1994

Circulating insulin-like growth factors-I and -II and substrates in fetal sheep following restriction of placental growth.

To determine the relationship between placental delivery of oxygen and glucose, circulating insulin-like growth factors (IGFs) and fetal growth, the effect of variable restriction of placental growth was determined in sheep in late gestation. Arterial blood was obtained via indwelling catheters at 120 and 127 days of gestation, prior to necropsy at 130 days to measure fetal and placental weights. Plasma was acidified and subjected to size-exclusion high-performance liquid chromatography at pH 2.8 to dissociate and separate IGFs from their binding proteins. The acid-dissociated IGF fraction was analysed by sensitive and highly specific radioligand assays for IGF-I and IGF-II, previously defined using ovine IGFs. Fetal weight and blood pO2 and glucose at 120 and 127 days of gestation correlated positively with placental weight. Plasma IGF-I was positively associated with fetal weight and fetal liver weight, and with blood pO2 and glucose at both ages. Plasma IGF-II levels also correlated positively with fetal weight, fetal liver weight and with blood glucose and pO2, but only at 127 days of gestation. In the most severely growth-retarded fetal sheep, blood glucose and pO2 and plasma IGF-I were significantly reduced when compared with normal fetuses at 120 days. All decreased further by 127 days of gestation as did plasma IGF-II in severely growth-retarded fetal sheep compared with normal fetuses. These observations are consistent with the hypothesis that both IGF-I and IGF-II are chronically regulated by oxygen and nutrition in utero and mediate part of the influence of placental supply of substrate over fetal growth.

Animals↗
PubMed1993

Role of gonadotrophin releasing hormone secretory dynamics in the control of the human menstrual cycle.

The pattern of episodic gonadotrophin releasing hormone (GnRH)-driven luteinizing hormone (LH) secretion changes dynamically across the human menstrual cycle. Adherence to a specific regimen of pulse amplitude and frequency is critical for normal ovulation, menstrual cyclicity and reproductive function. Derangements of episodic LH secretion are associated with anovulation. We have shown that in the human slowing of GnRH-induced LH pulses results in lower ovulatory rates and dysfunctions of the mid-cycle LH surge. This information is relevant for the understanding of the endocrine dynamics of the menstrual cycle both in normal and anovulatory subjects.

Anovulation↗
PubMed1992

Induction of antigen-specific class I-restricted cytotoxic T cells by soluble proteins in vivo.

Cytotoxic T lymphocytes (CTL) are induced specifically against viral and tumor antigens presented by major histocompatibility complex class I molecules on the surface of infected or transformed cells. Intracellular synthesized antigens are processed and associated with class I antigens within cells before presentation on the cell surface. Because of this special requirement for CTL induction, exogenous soluble antigens do not, in general, induce specific CTL responses. To overcome this problem, various laboratories have resorted to the use of vaccinia virus and other replicating expression vectors for intracellular antigen delivery leading to the stimulation of humoral and cell-mediated immunity to specific proteins. However, for human use it is safer to use purified and defined antigens for inducing immune responses. Using soluble ovalbumin and human immunodeficiency virus glycoprotein gp120, we have explored the possibility of using an antigen formulation consisting of squalane and Tween 80 to elicit antigen-specific CTL responses in mice. We have demonstrated that this antigen formulation is a potent inducer of CD8+, class I-restricted, antigen-specific CTLs. The CTL priming induced by soluble antigen in squalane/Tween 80 resembles the reported response to the vaccinia recombinant containing human immunodeficiency virus envelope protein and by splenocytes cytoplasmically loaded with soluble ovalbumin. The ramifications of these findings for vaccine development are discussed.

Adjuvants, Immunologic↗
PubMed1991

pH sensitive liposomes provide an efficient means of sensitizing target cells to class I restricted CTL recognition of a soluble protein.

Exogenous antigens are normally endocytosed and enter the class II pathway of processing and presentation. It had been shown earlier that soluble antigen could be introduced into the class I pathway of processing and presentation by osmotic loading. In this report, we have demonstrated that OVA containing liposomes that destabilize on exposure to low pH, referred to as pH sensitive liposomes, could sensitize target cells to lysis by class I MHC-restricted OVA-specific CTL. However, OVA-containing pH insensitive liposomes, native OVA, or OVA subjected to the same protocol as was used to make the liposomes, failed to sensitize targets to OVA-specific CTL lysis. The pH sensitive liposomal approach was less toxic and more efficient (about 20-fold) in delivering than the osmotic loading approach. The pH liposome approach may prove valuable to study CTL recognition characteristics of less available proteins such as viral proteins.

Animals↗
PubMed1989

[Regressive atypical histiocytosis (or Ki-1 lymphoma of the skin). Presentation of a case with an immunohistochemical study].

The Authors report a case of regressing atypical histiocytosis (or lymphoma Ki-1 of the skin) a primary cutaneous neoplasm composed by atypical cells resembling histiocytes and proliferating on a inflammatory background. The course is more frequently indolent with healing, although cases with evolution to a systemic lymphoma are referred. The case reported concerns a 52 years old man with multiple lesions in several sites of the body. Ours immuno-histochemical investigations have shown positivity for Ber H2 (equivalent to Ki-1) and for T line monoclonal antibodies in the proliferating cells. Our results agree with the recent reports of literature and therefore that lesion, at first believed as composed by histiocytes, is more probably a neoplasia of the T cells lineage.

Biopsy↗
PubMed1988

Structure-activity studies of melatonin analogues in prepubertal male rats.

Comparison has been made between the activity of the pineal hormone melatonin, and several analogues and metabolites in inhibiting sexual development in a protein-restricted prepubertal rat model. Eleven melatonin analogues or metabolites were tested with the aim of evaluating the model as a test of the hypothesis that melatonin acts as a prohormone and that the ring schism metabolites (kynurenamines) mediate many of the effects attributable to melatonin. Although the hypothesis could not be confirmed, modification of the melatonin structure by lengthening the acrylamide side chain or by replacing the 5 methoxy function with fluorine resulted in loss of biological potency. Modification of the melatonin structure to block the two known points of metabolism resulted in no significant alteration in biological activity. Thus 6-chloromelatonin (blocking 6-hydroxylation) and 2,3-dihydromelatonin (blocking oxidative cleavage of the C2-C3 bond) and 6-chloro-2,3-dihydromelatonin remained biologically active. The metabolic products of brain indoleamine-2,3-dioxygenase, N-acetyl-N2-formyl-5-methoxy kynurenamine (aFoMK) and N-acetyl-5-methoxy kynurenamine (aMK), paradoxically were also biologically active.

Animals↗
PubMed1988

Effects of protein restriction, melatonin administration, and short daylength on brain benzodiazepine receptors in prepubertal male rats.

The possibility that there are changes in brain benzodiazepine binding sites controlled by photoperiod was investigated in two strains of male rats. The hypothesis was tested by 3H-diazepam binding studies in various brain regions of prepubertal rats maintained in 14 or 10 h of light or treated with late-afternoon injections of melatonin (50 micrograms/day). Protein restriction was applied during the experiment to sensitise the animals to the treatments. Under the conditions employed, rats kept in short daylength throughout or kept on long photoperiod and given late-afternoon melatonin injections showed evidence of delayed puberty (seminal vesicle, ventral prostate, and testis weight decreased by 45%, 55%, and 60% respectively, compared to control rats). Binding measurements were made 1 h before and 2 and 5 h after the onset of darkness in the pubertal (42-day-old) or experimentally prepubertal rats. In the rats of the Porton strain (for which protein restriction was obligatory for the gonadal response) there was no consistent treatment or time effects on specific binding of 3H-diazepam to washed membranes of the hypothalamus, midbrain, or striatum. Similarly, there were no differences in the stimulation of 3H-diazepam binding by 100 microM GABA or the inhibition of binding by 50 microM N-acetyl 5 methoxy kynurenamine. By contrast, in Wistar rats, specific binding to midbrain membranes was reduced 5 h after dark compared to 2 h (37% saline; 20% melatonin) and the extent of stimulation by GABA in the hypothalamus was increased 5 h after darkness (35.6% to 46.7% saline; 37.4% to 50% melatonin). Melatonin treatment resulted in significantly higher specific binding in the hypothalamus 2 h after dark (10%, control fed; 20%, protein restricted) but reduced the GABA induced stimulation of binding in the midbrain (35.5% to 25%, control fed; 33.7% to 23.5%, protein restricted). The Bmax of benzodiazepine binding to unwashed cortical P2 synaptosomal membranes has been reported to increase twofold in adult Wistar rats at mid-dark. By contrast the Bmax of juvenile Wistar rats in this study increased only 17% (116 +/- 2.4 fmol/mg protein to 140 +/- 3 fmol/mg protein) between 2 and 5 h after darkness. In melatonin-treated animals the increase in Bmax of 3H-diazepam binding was blocked (124 +/- 5 fmol/mg protein at 2 h; 127 +/- 3 fmol/mg protein at 5 h) and the Kd reduced (4.5 +/- 0.5 to 4.0 +/- 0.2 nM).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Phase delay of the rhythm of 6-sulphatoxy melatonin excretion by artificial light.

The purpose of this study was to investigate the effect of bright artificial light exposure on the rhythms of 6-sulphatoxy melatonin and cortisol excretion in urine. Six healthy males were exposed to light (greater than 3,000 lux) from 1900 to 0200 h (sunset 1928 h) on one occasion. The artificial light delayed the onset of 6-sulphatoxy melatonin excretion. On the next evening the onset of 6-sulphatoxy melatonin excretion in normal light/darkness was delayed by 1 h. The timing of the peak excretion of cortisol was not affected by the light treatment; however, cortisol excretion rate was maintained at a significantly higher rate in the morning and afternoon after the treatment. These results demonstrate the inhibitory action of high intensity light in humans and suggest that one 6-h period of extra light in the evening can phase delay the melatonin onset.

Adult↗