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Biomedical subjects

F Ricci

Publications and source records attributed to F Ricci.

At least 91 records · Page 5Linked to original sources
PubMed1995

Effect of antidenaturant drugs on lysozyme deposit formation on soft contact lenses by liquid chromatography--electrochemical detection.

The effect of some antidenaturant drugs on the formation of lysozyme deposits on soft contact lenses was investigated by in vitro experiments. Results were obtained which encourage the use of this strategy to reduce lens spoilage. At the same time emphasis is given to the possibility that some functionalities (i.e. lysine groups) present in drug molecules could promote protein adsorption. In order to evaluate at a quantitative level the effectiveness of the drugs used to minimize the formation of deposits on soft contact lenses, a selective method for the determination of adsorbed lysozyme was developed. It is based on the hydrolysis of the 'lens/adsorbed lysozyme' system, followed by high performance liquid chromatography coupled to electrochemical detection of the released tryptophan residues. The lysozyme calibration curve was linear up to 5 mg ml-1 and the detection limit was 5 ng injected.

Adsorption↗
PubMed1995

Benign cystic mesothelioma in a male patient: surgical treatment by the laparoscopic route.

We report a case of a benign cystic mesothelioma in a 44-year-old man. The patient was asymptomatic, and the cystic formation was discovered by chance in the course of ultrasonography for urological disorders. Benign cystic mesothelioma is a rare pathology, and only 19 cases have been described in male patients. The differential diagnosis versus other cystic diseases can only be defined histologically and is of critical importance to clinical management. Surgery is mandatory for both diagnosis and treatment. In the case reported here, a minimally invasive laparoscopic approach allowed not only histological diagnosis of benign cystic mesothelioma, but also its surgical treatment by the same route.

Adult↗
PubMed1995

[Lactic acidosis induced by phenformin: a still forgotten iatrogenic complication].

Phenformin, a drug used in the treatment of diabetes mellitus frequently associated with potentially fatal cases of lactic acidosis, has been removed from market in the USA and several European countries. However, cases of lactic acidosis are still reported in countries where phenformin is available, either because well-known contraindications for its use are not observed, or because the prodromic syndrome of the lactic acidosis is not diagnosed. This study describes two cases of lactic acidosis, the treatment used and the final outcome. The authors point out that plainly evident contraindications were ignored in both cases, while the prodromic syndrome remained unrecognized even by specialists. The management of lactic acidosis continues to be a challenge. There is no optimal treatment and early recognition is essential. The authors call for greater attention in the use of phenformin and its eventual removal from market, especially in the light of alternative therapies which prove to be equally valid and easier to administer.

Acidosis, Lactic↗
PubMed1994

Microvascular lesions in reflux oesophagitis and Barrett's oesophagus.

In 30 patients with reflux oesophagitis, the mucosal microvessels have been studied by transmission electron microscopy. The aim of the study was to test the hypothesis that a microvascular injury is involved in reflux oesophagitis, and to clarify if the epithelial metaplasia is correlated with a contemporaneous modification of the microvasculature in Barrett's oesophagus. In squamous epithelium-lined mucosa, signs of microangiopathy were found in all patients and capillaries regularly showed an interrupted, duplicated, or thickened basal lamina. In areas of columnar metaplasia, capillaries showed an ectatic lumen and a thin basal lamina without duplications or interruptions; endothelial cells had a thin rim of cytoplasm with many fenestrations. These findings demonstrate that microangiopathy is associated with epithelial damage in reflux oesophagitis.

Adult↗
PubMed1993

Combined treatments with interferon (alpha,beta) plus PGA1 to control early infection with HTLV-I in primary cord blood-derived mononuclear cells.

Interferon (IFN) alpha and beta can activate an antiviral and immunomodulating response in primary cord blood-derived mononuclear cells (CBMC) exposed to infection with Human T-cell Leukemia Virus type I (HTLV-I), resulting in partial inhibition of early infection in vitro. On the other hand, PGA1, a PGE1-derived cyclopentenone prostaglandin, can inhibit in vitro the proliferation of virus-infected CBMC, preventing the emergence of the potentially transformed clone. In order to achieve a complete control of HTLV-I infection in this experimental model, we evaluated whether the antiviral activity of IFNs and the antiproliferative activity of PGA1 could be preserved in a combination therapy scheme. Recipient CBMC were treated with IFN alpha or beta (1000 IU/ml) at the onset of the co-culture with lethally irradiated virus-donor MT-2 cells, followed by multiple treatments with PGA1 (4 micrograms/ml every 4 days, starting on day 0) for 6 weeks post infection (p.i.). In PGA1-treated co-cultures the percentage of virus-positive CBMC was constantly doubled during culture time as well as the amount of viral transcripts and p19 virus core protein production were increased. The antiviral effects of IFNs, resulting in about a 50% reduction of the percentage of virus-positive CBMC and consequently in a partial inhibition of virus expression (HTLV-I transcription and p19 production) until 4 weeks p.i., were suppressed by multiple PGA1 treatments. However, the antiproliferative effect of PGA1 was enforced in IFN-treated co-cultures, leading to earlier control of proliferation of virus-infected cells. Interestingly, infection of CBMC with HTLV-I was associated with persistent expression of 70 kDa heat shock protein (HSP70), for at least 4 weeks p.i. IFNs and PGA1 showed antagonistic effects on HSP70 production in infected CBMC. In fact, production of HSP70 was suppressed (or prevented) in IFN-treated co-cultures, tested 2 and 4 weeks p.i. The fact that the expression of HSP70 is apparently suppressed (or prevented) by IFN treatment is surprising, since expression of this protein family has been associated with antiviral immunity. PGA1 could totally reverse the IFN-mediated suppression of HSP70 expression in these co-cultures. It is presently unclear whether HSP70 expression is directly involved in the control of proliferation exerted by PGA1 against virus-infected CBMC or is an epiphenomenon associated with inhibition of cell growth.

Cell Division↗
PubMed1993

A randomized controlled trial of a new PEG-electrolyte solution compared with a standard preparation for colonoscopy.

The efficacy, tolerability and patient acceptance of a new flavoured PEG solution for gut lavage was compared with a standard preparation for bowel cleansing in a randomized controlled trial of patients undergoing colonoscopy. One hundred and sixty patients were randomly allocated either to a standard preparation (2-day semi-liquid diet, laxatives and cleansing enemas) or to gut lavage (fractionalized ingestion of lavage solution, two litres in the afternoon before and a third litre the morning of the examination). Adequacy of colon cleansing was scored evaluating residual stool in each colonic segment and overall mucosal visibility. Tolerability of methods was assessed by evaluating the incidence and severity of side-effects. Patient acceptance was graded (good, fair to good, poor) according to the patient's judgement about the ease of execution and interference with sleep and working activity. Less residual stool (p < 0.05) and better visualization of colonic mucosa (p < 0.05) were obtained with gut lavage than with standard preparation. Both methods were well-tolerated and a low incidence of side effects was recorded in both groups. Patient acceptance was good in more than 80% of patients in both groups. We conclude that gut lavage is a rapid, effective and well-tolerated method for bowel cleansing. The use of a flavoured solution in a fractionalized schedule seems to improve the tolerability and the patient acceptance of this method.

Adolescent↗
PubMed1992

Acute cholecystitis: ultrasonographic staging and percutaneous cholecystostomy.

Experience in the treatment of acute cholecystitis with percutaneous cholecystostomy in 29 high-risk and elderly patients is reported. The treatment group included 14 men and 15 women, 21 of whom were over 70 years of age. The suspected clinical diagnosis of acute cholecystitis was confirmed in all cases by ultrasonography (accuracy: 95.6%). The percutaneous cholecystostomy was successful in 27 of 29 cases and these patients had a sudden improvement in their clinical condition; failure of the procedure was due in one patient to dislodgement of the catheter and in another patient to the guide-wire slipping out of the gallbladder. Six patients complained of pain radiating to the right shoulder which disappeared within 30-60 minutes after the procedure. Twenty-three of the 27 patients subsequently underwent elective cholecystectomy. In 22 patients the ultrasonographic findings were compared with the histology; thus enabling us to establish an ultrasonographic staging of acute cholecystitis related to the seriousness of the disease. Percutaneous cholecystostomy is the treatment of choice in high-risk patients, in the elderly, as well as in young patients with impending perforation.

Acute Disease↗
PubMed1992

Two methods of examining protein deposits on hydrophilic contact lenses.

Our aim in these studies has been to develop spectroscopic techniques for quantitative analysis of the early phases of protein deposition on soft contact lenses. We produced protein deposition in vitro by soaking lenses in a 0.025% chloral hydrate lysozyme solution at 37 degrees C. Two groups of lenses were so treated: one for 15 days and the other for 6 months. The study of in vivo deposits was carried out on lenses used by healthy wearers. From the same six patients we obtained two consecutive groups of 12 lenses: one group worn for 8 hours and the other group worn for 7 days. We tested the lenses by an indirect (destructive) method (based on a colorimetric assay of amino acid complexes obtained by basic hydrolysis) and by a direct (non-destructive) method consisting of spectrophotometry performed on intact lenses. Using the indirect method we found that the lenses absorbed in vitro for 6 months had lysozyme deposits of 5 +/- 1 micrograms; while the lenses adsorbed for 15 days supplied an average of 0.8 +/- 0.3 micrograms of lysozyme. Lenses worn by healthy volunteers show protein deposition equivalent to a lysozyme quantity ranging from 0.8 to 1.6 micrograms. We found a lower limit of detection with the direct method of approximately 5 micrograms, limiting its applicability.

Adsorption↗