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A Chiappetta

Publications and source records attributed to A Chiappetta.

13 recordsLinked to original sources
PubMed2001

Short- and long-term effects of dehydroascorbate in Lupinus albus and Allium cepa roots.

Administration of 1 mM dehydroascorbate (DHA) results in a rapid and large increase in cellular ascorbate (AA) content in both Lupinus albus L. and Allium cepa L. root tips. Uptake of DHA from the medium occurs at a high rate within 10-12 h of incubation, and is slowed down thereafter. In the first few h, DHA reduction to AA is apparently correlated to GSH depletion and slightly higher DHA reductase activity. DHA incubation also seems to induce new GSH synthesis. Longer DHA incubation (24 h) affects root growth by inhibiting cell proliferation. At this stage, an apparently generalised oxidation of SH-containing proteins is observed in DHA-treated roots. Treatment with 1 mM L-galactono-gamma-lactone, the last precursor of AA biosynthesis, results in an increase in AA content similar to that obtained with DHA, but stimulates growth and affects the redox state of SH-containing proteins in the opposite way. A possible multi-step mechanism of DHA reduction/removal is suggested and the hypothesis that DHA inhibits cell cycle progression by affecting the redox state of SH-containing proteins is discussed.

Cell Division↗
PubMed2001

Overexpression of KNAT1 in lettuce shifts leaf determinate growth to a shoot-like indeterminate growth associated with an accumulation of isopentenyl-type cytokinins.

Leaves are specialized organs characterized by defined developmental destiny and determinate growth. The overexpression of Knotted1-like homeobox genes in different species has been shown to alter leaf shape and development, but a definite role for this class of genes remains to be established. Transgenics that overexpress Knotted1-like genes present some traits that are characteristic of altered cytokinin physiology. Here we show that lettuce (Lactuca sativa) leaves that overexpress KNAT1, an Arabidopsis kn1-like gene, acquire characteristics of indeterminate growth typical of the shoot and that this cell fate change is associated with the accumulation of specific types of cytokinins. The possibility that the phenotypic effects of KNAT1 overexpression may arise primarily from the modulation of local ratios of different cytokinins is discussed.

Arabidopsis Proteins↗
PubMed1999

Amount and organization of the heterochromatin in Olea europaea and related species.

The amount and spatial organization of the heterochromatin in nuclei of the shoot meristem and the frequency in the nuclear DNA of sequences belonging to a family of tandem repeats were investigated in cultivars of Olea europaea and related species. Significant differences between Olea species and between cultivars of O. europaea were observed: (i) in the spatial organization of the heterochromatin in interphase nuclei as determined by the number and surface area of the chromocentres; (ii) in genome size; and (iii) in the amount of condensed chromatin as measured by cytophotometry carried out at different thresholds of optical density. DNA elements belonging to a family of tandem repeats about 80 bp in length (OeTaq80 repeats) were isolated from the genomic DNA of an olive cultivar. It was shown: (i) by nucleotide sequence comparisons, that these repeats display variability in structure even within the same array, where different elements may share no more than 74% homology; (ii) by in situ hybridization, that OeTaq80-related DNA sequences are mainly localized in the heterochromatin at the chromosome ends; (iii) by dot-blot hybridization experiments, that these sequences are highly represented in the genome of all the olive cultivars and the majority of Olea species studied, and that their frequency may differ significantly even between olive cultivars; and (iv) by calculating the copy number of OeTaq80-related sequences per haploid (1C) genome, that the redundancy of these DNA elements may differ significantly between the genomes tested. It is suggested that the inter- and intraspecific changes in the nuclear and genomic traits observed can contribute to the understanding of the phylogenetic relationships between Olea species and in defining parameters to be exploited in varietal identification within cultivated olives.

Base Sequence↗
PubMed1999

Dynamics of cytokinins in apical shoot meristems of a day-neutral tobacco during floral transition and flower formation

This study considered cytokinin distribution in tobacco (Nicotiana tabacum L.) shoot apices in distinct phases of development using immunocytochemistry and quantitative tandem mass spectrometry. In contrast to vegetative apices and flower buds, we detected no free cytokinin bases (zeatin, dihydrozeatin, or isopentenyladenine) in prefloral transition apices. We also observed a 3-fold decrease in the content of cytokinin ribosides (zeatin riboside, dihydrozeatin riboside, and isopentenyladenosine) during this transition phase. The group concluded that organ formation (e.g. leaves and flowers) is characterized by enhanced cytokinin content, in contrast to the very low endogenous cytokinin levels found in prefloral transition apices, which showed no organogenesis. The immunocytochemical analyses revealed a differing intracellular localization of the cytokinin bases. Dihydrozeatin and isopentenyladenine were mainly cytoplasmic and perinuclear, whereas zeatin showed a clear-cut nuclear labeling. To our knowledge, this is the first time that this phenomenon has been reported. Cytokinins do not seem to act as positive effectors in the prefloral transition phase in tobacco shoot apices. Furthermore, the differences in distribution at the cellular level may be indicative of a specific physiological role of zeatin in nuclear processes.

Journal Article↗
PubMed1995

[Laparoscopic cholecystectomy for gallbladder stones].

The authors describe the technique for the treatment of gallbladder stones using a laparoscopic approach and discuss the diagnostic and operative flow chart stressing complications and ways to avoid them. A total of 2517 non-selected patients underwent surgery since october 1990 up to september 1995. 252 were affected by acute cholecystitis (10%); 172 underwent emergency laparoscopic cholecystectomy. ERCP was performed in 278 patients (11.04%): 177 underwent endoscopic sphincterotomy and laparoscopic cholecystectomy, 21 underwent laparoscopic cholecystectomy before sphincterotomy, 8 laparoscopic cholecystectomy and ESWL. Laparoscopic cholecystectomy was converted into laparotomy in 37 patients (1.4%); surgery was abandoned in 3 patients following to onset of intense bradycardia. Major complications were observed in 0.63%; bile duct injury occurred in four patients (0.15%). One patient died following a massive intraoperative myocardial infarction. Average operative time was 21 minutes. Only 22.8% of patients required mild analgesia on the first day after surgery. The average hospital postoperative stay was 2.6 days. Return to work took place in 98% of non complicated patients within one week of being discharged from hospital.

Cholecystectomy, Laparoscopic↗
PubMed1995

Congenital choledochal cyst: video-guided laparoscopic treatment.

We report our first experience with a laparoscopic treatment of congenital choledochal cysts involving the total cyst resection and the reconstruction of the biliary and gastrointestinal tracts through a transmesocolic hepatic-jejunal Roux-en-Y loop anastomosis. The procedure was carried out in a 14-kg 6-year-old girl with a congenital choledochal cyst of the first type, according to the Alonso-Lej classification. The cyst was divided using a Multifire EndoGIA 30 stapler. Hepatic-jejunal and jejunojejunal anastomoses were made with 4.0 chrome catgut interrupted sutures. Intestinal recanalization occurred on the 2nd postoperative day and the postoperative course was uneventful. The laparoscopic approach affords several advantages: excellent intraoperative visualization of tiny structures and, therefore, great surgical accuracy; early resumption of peristalsis; no postoperative pain; no laparocele; prevention of adhesions; excellent esthetics; and quicker resumption of school and sports activities.

Anastomosis, Roux-en-Y↗
PubMed1993

[Choledochoduodenal anastomosis by laparoscopy].

Eleven patients underwent choledochoduodenostomy under laparoscopic control: 5 for adenocarcinoma of head of pancreas, including 2 with extension into duodenum, 3 for chronic pancreatitis. 1 for gastric carcinoma with pancreatic infiltration 1 for carcinoma of ampulla and 1 for stenosing papillitis. Mean duration of operation was 97.9 minutes and mean hospital stay 7.8 days. No immediate or delayed postoperative complications were reported. The advantages of this method are the marked reduction in recovery time, especially in severely debilitated elderly patients, and the absence of postoperative pain.

Adenocarcinoma↗
PubMed1992

[Laparoscopic cholecystectomy using argon bistoury].

A total of 92 patients were submitted to laparoscopic cholecystectomy during the period Autumn 1990-Spring 1991. The dissection of the gallbladder from the hepatic bed was performed in 40 patients using the Argon beam coagulator, in 25 using the monopolar electrocoagulator and in 27 using the Holmio laser beam. In average, with the Argon beam coagulator time procedure was respectively 2.7 and 5.4 minutes shorter than monopolar electrocoagulator and Holmio laser. Only one complication (pneumomediastinum) was correlated with the use of the Argon beam coagulator.

Adult↗
PubMed1986

Surgical experience with adenocarcinoma of the ampulla of Vater.

Between 1968 and 1982, 13 patients in this study had a pancreaticoduodenectomy (PD), one patient had a total pancreatectomy, two had an ampullectomy, and one patient had a choledochoduodenostomy for neoplasia of the ampulla of Vater. The operative mortality was zero, and the 5-year actuarial survival rate for the 16 resected patients was 52.6 per cent. From a review of the literature, the authors evaluated 1,894 PDs and 61 ampullectomies. The operative mortality rate was 14 per cent and 3 per cent, respectively. The 5-year survival rate was 21 per cent for PD and 23 per cent for ampullectomy. However, 187 patients with negative lymph nodes who underwent PD had a 5-year survival rate of 39 per cent. PD resection is fully warranted for ampullary tumors. Ampullectomy should be reserved only for high surgical risk patients.

Adenocarcinoma↗
PubMed1984

Duodenal leiomyosarcoma and its multiple recurrences: good surgical result after three years of follow-up.

Duodenal leiomyosarcoma is a rare tumor and its current prognosis is poor. A case of duodenal leiomyosarcoma is described which recurred five years after the first intestinal resection, and was treated successfully with pancreaticoduodenectomy (PCD), extensive small bowel resection, and transverse, descending and sigmoid colon removal. The patient is still alive three years after this operation. Preservation of the stomach and the first duodenal portion after PCD most likely reduced the malabsorption, which is expected following such radical intestinal resection. This experience suggests an aggressive surgical approach to duodenal leiomyosarcomas, even when metastases are present.

Bile Ducts↗
PubMed1983

[Chronic pancreatitis and diabetes].

Chronic pancreatitis appears to be increasing likely because increase in alcohol consumption and improved diagnostic tools. So the diabetes due to chronic pancreatitis is gaining importance. In order to obtain a better understanding of that particular secondary diabetes, 179 patients with chronic pancreatitis were studied from 1970 to 1981. 154 patients were male and 25 female. Average admission age was 45, ranging from 25 to 86. All the patients underwent medical therapy, based on diet, pancreatic enzymes, pain control. 99 of them underwent even to surgery. The follow-up is ranging from 6 months to 10 years: during this period 18 patients died, 41 went lost. 120 patients are still under observation. Diabetes was found in the family history of 27 patients (15%). At hospital admission 41 patients (23%) had high fasting glycemia, 23 of them even glycosuria. Other 74 showed diabetic oral glucose tolerance test. During the follow-up time 27 became clinically diabetic, 3 died because hyperosmolar coma and 8 had to be readmitted more than once because diabetic metabolic decompensation. Among the 120 patients at the moment under control, 66 (55%) show abnormal fasting glycemia, 10 developed high blood pressure, 12 inferior limbs vasculopathy with paresthesias and intermittent claudication, 2 myocardiosclerosis and atrial fibrillation, 1 myocardial infarction, 2 chronic nephropathy, 1 diabetic retinopathy. Whereas surgery or medic therapy may relieve chronic pancreatitis typical symptoms, they appear to be useless remedy against the under lying diabetes. As the time goes on more and more patients develop glucose intolerance, quite early became insulin-dependent, are disposed to severe diabetic metabolic decompensation and can show vascular, cardiac or renal complication.

Adult↗
PubMed1983

Cystic neoplasms of the pancreas.

Seven cases of cystic neoplasms of the pancreas (5 cystadenomata and 2 cystadenocarcinomata) are reported. While cystadenomata were localized in the tail of pancreas, cystadenocarcinomata were localized in the head. Only one case was asymptomatic and evidenced in the course of other type of surgery. Preoperative diagnosis of cystadenoma was assessed only in one case. All benign forms were treated with radical resection. Only palliation was possible for malignant forms. The moderate malignancy of cystic tumors as compared to the more common pancreatic adenocarcinoma is underlined. A more careful intraoperative diagnosis and surgical resection are therefore advocated, whenever possible.

Adult↗