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Biomedical subjects

A Meroni

Publications and source records attributed to A Meroni.

At least 19 recordsLinked to original sources
PubMed2004

Electroclinical, MRI and neuropathological study of 10 patients with nodular heterotopia, with surgical outcomes.

We present the results of a retrospective study on 10 patients operated on for intractable epilepsy associated with nodular heterotopia as identified by high resolution MRI. Seven patients had unilateral heterotopia, one patient had symmetric bilateral heterotopia and two patients had asymmetric bilateral heterotopia. By stereo-electroencephalogram (SEEG) (nine patients) interictal activity within nodules was similar in all cases, and ictal activity never started from nodules alone but from the overlying cortex or simultaneously in nodules and cortex. Excellent outcomes (Engel class Ia, 1987) were achieved in the seven patients with unilateral heterotopia, showing that surgery can be highly beneficial in such cases when the epileptogenic zone is carefully located prior to surgery by MRI and particularly SEEG. For the bilateral cases surgical outcomes were Engel IIa (one patient) or Engel IIIa (two patients). Histological/immunohistochemical studies of resected specimens showed that all nodules had similar microscopic organization, even though their extent and location varied markedly. The overlying cortex was dysplastic in nine patients, but of normal thickness. We suggest that nodule formation may be the result of a dual mechanism: (i) failure of a stop signal in the germinal periventricular region leading to cell overproduction; and (ii) early transformation of radial glial cells into astrocytes resulting in defective neuronal migration. The intrinsic interictal epileptiform activity of nodules may be due to an impaired intranodular GABAergic system.

Adult↗
PubMed2001

Chondroitin sulfate proteoglycans in the rat thalamus: expression during postnatal development and correlation with calcium-binding proteins in adults.

Postnatal expression of chondroitin sulfate proteoglycans was studied in the rat thalamus by immunocytochemistry and Western immunoblotting techniques with monoclonal antibodies that recognize carbohydrate epitopes (clones CS-56, 1-B-5, 2-B-6). The complex of the results shows that these antibodies recognize mostly nonoverlapping molecules whose expression is regulated during postnatal development. Chondroitin sulfate proteoglycans, recognized by antibody CS-56, and hyaluronan, identified by antibody 1-B-5 after hyaluronidase digestion, are abundant in the neuropil of most thalamic nuclei at the perinatal stage and progressively decrease during the second week of life, attaining levels barely detectable by immunocytochemistry at the end of the third week. In adult thalamus, chondroitin sulfate proteoglycans of high molecular mass, bearing glycosaminoglycans unsulfated in the linking region, and recognized by antibody 1-B-5 are confined to perineuronal nets around neurons chiefly localized in thalamic reticular nucleus. The immunoreactvity for antibody 2-B-6, specific for chondroitin-4-sulfate, is low at the perinatal stage and is not detectable in adult thalamus. Double-immunolabeling has shown that, along the rostrocaudal extension of reticular nucleus, the most developed perineuronal nets are associated with a subset of neurons expressing calretinin, and not with parvalbumin-positive neurons, which represent the largest neuronal population of the nucleus. The distribution of perineuronal nets supports the presence, in thalamic reticular nucleus, of neuronal subpopulations with different morphological and physiological features.

Animals↗
PubMed2000

Pulmonary resection for lung cancer in HIV-positive patients with low (<200 lymphocytes/mm(3)) CD4(+) count.

The clinical improvement obtained with combination treatment has modified the therapeutic approach of lung cancer in HIV-positive patients. Aggressive surgical treatment has become a viable option for those patients in whom the CD4(+) cell count was greater than 200 lymphocytes/mm(3). We recently extended our surgical indications to include two HIV-positive patients with lung cancer (stage IIIA and IIB) and low (<200 lymphocytes/mm(3)) CD4(+) count. Both patients underwent a lobectomy and mediastinal nodal dissection. The postoperative course was uneventful. No evidence of recurrent cancer was seen at 12 and 20 months after the operation. Based on this limited experience, we conclude that a low CD4(+) count should not represent, per se, an exclusion criterion for the surgical treatment of pleuropulmonary conditions in HIV-positive patients.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Prognostic factors after surgical treatment of lung cancer invading the diaphragm.

BACKGROUND: Diaphragmatic invasion from lung cancer (T3-diaphragm) is a rare occurrence reported to portend a poor prognosis. METHODS: Fifteen patients with T3-diaphragm (14 males, 1 female; median age, 64 years) were surgically treated over a twenty-year period by en bloc resection (14 patients). One patient was only explored. Pathologic stage IIB (T3N0) was found in 11 patients. A partial infiltration of the diaphragm was observed in 3 patients, whereas full-depth invasion was found in 12. Diaphragmatic reconstruction was done primarily in 9 patients, and, by prosthetic material in 5. RESULTS: Two patients are still alive without evidence of disease at 88, and, 114 months from surgery. Overall median survival was 23 months (range, 3 to 168). The actuarial 5-year survival was 20%, when all patients were considered, and, 27%, for T3N0 patients. Univariate analysis showed that prosthetic replacement of the muscle (p = 0.018) was significantly related to survival. CONCLUSIONS: T3-diaphragm is best treated with en bloc resections with wide tumor-free margins and prosthetic replacement of the diaphragm.

Adult↗
PubMed1998

Hepatocellular carcinoma: comparison between liver transplantation, resective surgery, ethanol injection, and chemoembolization.

Between January 1989 and June 1997, 533 patients (423 male, 110 female, mean age 61 years, range 22-89 years) with hepatocellular carcinoma (HCC) were observed at our center. We report on 419 patients retrospectively compared for different treatments: liver transplantation (LT; 55 patients), resective surgery (RS; 41 patients), transarterial chemoembolization (TACE; 171 patients) and percutaneous ethanol injection (PEI; 152 patients). The 3- and 5-year actuarial survival rates were, respectively, 72% and 68% for LT, 64 and 44% for RS, 54 and 36% for PEI, and 32 and 22% for TACE. Survival curves were compared for sex, age, tumor characteristics, alphafetoprotein level, Child class, and etiology of cirrhosis. All patient-related characteristics examined (sex, age) are not significantly related to patient survival. Tumor-related variables and associated liver disease variables significantly conditioned survival in relation to different treatments. LT seems to be the treatment of choice for monofocal HCC less then 5 cm in diameter and in selected cases of plurifocal HCC.

Actuarial Analysis↗
PubMed1996

Ultrastructural characterization of the postnatal development of the thalamic ventrobasal and reticular nuclei in the rat.

Electron microscopy has been employed to analyze the normal maturational sequence that characterizes the postnatal development of synaptic circuits in the ventrobasal (VB) and reticular (Rt) thalamic nuclei of rats at different ages (from birth to the end of the third postnatal week). Throughout the first postnatal week, similar signs of immaturity are observed in both nuclei, mainly consisting in scarcity of cytoplasmic organelles, presence of wide extracellular spaces, and absence of myelinated fibers. Several synaptic terminals are however present from birth, thus indicating that some of the afferents have already reached and contacted their thalamic target during embryonic life. Most of the terminals are small and contain only a few round, clear vesicles, and therefore their cytological features do not allow the identification of their origin. In particular, in both nuclei, terminals with flat vesicles and symmetric specialization are only rarely observed, and in VB the ascending terminals are not distinguishable from terminals of other sources as they are in adults. During the second postnatal week, progressive maturational changes in VB and Rt lead to neurons having well-developed cytoplasmic organelles and to an elaborate neuropil containing myelinated fibers and synaptic terminals that are morphologically heterogeneous and resemble the adult ones. The permanence of growth cone-like profiles and of numerous somatic and dendritic protrusions, often contacted by synaptic terminals, indicates that a certain degree of reorganization is still taking place in both nuclei. By the end of the third postnatal week the synaptic organization of VB and Rt is indistinguishable from that observed in adults. This ultrastructural study shows that the appearance of the neuropil of VB and Rt and the morphological complexity of the synaptic arrangements characteristic of the adult rat are not present in neonates, but are gradually acquired during the first three postnatal weeks, and that they result from progressive modifications in circuit organization involving both pre- and postsynaptic elements.

Animals↗
PubMed1991

Biliary complications in orthotopic liver transplantation: experience with a modified technique of duct-to-duct reconstruction.

Biliary complications are described as frequent causes of morbidity during the postoperative course of orthotopic liver transplantation (OLTx), even in recent papers. The authors report here on their experience with duct-to-duct anastomosis as their method of choice for biliary reconstruction in a consecutive series of 100 OLTx in adult patients. The original technique, as described by Starzl, was modified by the authors by performing a wide, longitudinal plasty of both the donor and recipient bile ducts, joined together with two polidioxanone running sutures, producing the effect of a side-to-side anastomosis. This technique was used in all procedures, even when a significant discrepancy was evident between the ducts (n = 10). Follow-up was completed in 100% of the patients for a period of 2-40 months (mean 13.1 months). Four major complications (4%) occurred including hepatic abscesses due to ascending cholangitis, T-tube dislocation, partial occlusion by a branch of the T-tube at the anastomotic site, and disruption of the bile duct after T-tube removal. In four other patients, transient abdominal pain followed removal of the stent. Neither strictures nor fistulas were observed. Choledochocholedochostomy on a T-tube stent represents, in our experience, the technique of choice for biliary reconstruction in OLTx. The procedure, as described in the present study, proved to be safe in preventing strictures and leakages and appears to be feasible in nearly 100% of all adult patients undergoing OLTx.

Adult↗
PubMed1988

The role of donor and recipient factors in initial renal graft non-function.

ATN is a deleterious problem in the outcome of kidney transplantation. This complication is usually related to multiple factors including donor parameters, surgical technique, ischemic time, and recipient variables. In order to develop prophylactic measures, out of 430 kidney transplants performed in our Department, a series of 90 consecutive cadaveric renal allografts has been considered in this study. The overall incidence of IGNF was 23/90 (25.5%). Kidneys from MOD revealed a lower rate of IGNF (7/35 = 20%) when compared with organs from SOD (16/55 = 29%, P = NS). No difference was noted when kidneys were removed together with heart and/or liver and/or pancreas. Out of the donor factors, only CID was significant (17 +/- 9 hours in IGNF v 11 +/- 10 hours in patients with IGF, P = less than .05). Analysis of data concerning the fate of paired kidneys revealed two cases of IGNF in both kidneys from the same donor v 14 cases of IGNF in only one of the two paired grafts (P = NS). We conclude that: 1. Donor factors are clearly associated with a minority of IGNF. 2. The introduction of multiorgan procurement programs does not complicate early function. 3. Recipient factors (immunological events and intraoperative fluid management) provides important additive effects on initial graft nonfunction.

Adolescent↗