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Biomedical subjects

A Ferretti

Publications and source records attributed to A Ferretti.

At least 55 records · Page 3Linked to original sources
PubMed1996

Antithromboxane activity of dietary alpha-linolenic acid: a pilot study.

Two decades of research conclusively demonstrated the antithrombotic properties of the long-chain n-3 polyunsaturated fatty acids (PUFA) present in lipids from marine fishes. Most American consumers, however, given their preference for meat, will not realize the benefits of a fish-rich diet. Could alpha-linolenic acid (18:3, n-3) be similarly effective via modulation of the synthesis of vasoactive eicosanoids, i.e., thromboxane and prostacyclin? The present pilot study is a contribution toward answering this question. We determined that the urinary excretion of 11-dehydrothromboxane B2 declined by 34% from baseline level 7 weeks after the n-6/n-3 ratio of dietary PUFA was reduced from 28:1 to 1:1. The excretion of 2,3-dinor-6-oxo-prostaglandin F1 alpha was similarly affected. The dietary adjustment was brought about by substituting measured amounts of canola and flaxseed oils (3:1) for measured amounts of olive and corn oils (3:1) in an otherwise fat-free basal diet. This study demonstrates that dietary alpha-linolenic acid is an effective modulator of thromboxane and prostacyclin biosynthesis. Therefore, we can expect that the eicosanoid-mediated effects of alpha-linolenic acid are similar to those elicited by marine lipids.

6-Ketoprostaglandin F1 alpha↗
PubMed1995

Mass spectrometric evidence for the anomalous chemical behavior of 11-dehydrothromboxane B2.

When we subjected 11-dehydrothromboxane B2 (11-DTXB2), a metabolite of arachidonic acid, to standard chemical derivatization procedures we obtained a mixture of several products. Separation of the components was carried out by gas chromatography and their identification was accomplished through the study of their mass spectra, which are presented here. Anomalous behaviors include methylation of allylic and alcoholic hydroxyl groups by diazomethane, unusually slow derivatization of one of the hydroxyl groups with N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA) and etherification of another with ethanol. The underlying causes of these abnormal behaviors are not obvious, but appear to be related, at least in part, to the opening/closure of a lactone ring in the molecule. These observations have some bearing on the development of valid procedures for GC-MS quantification of this important marker of thromboxane A2 synthesis in vivo, and of similar compounds.

Diazomethane↗
PubMed1995

Neutrophil functions in essential thrombocythemia.

Chronic myeloproliferative diseases, such as chronic myeloid leukemia and polycythemia vera, are associated with neutrophil dysfunction. Very little data is available on essential thrombocythemia (ET). In the current study we evaluated 21 patients with ET. All patients were studied at least 16 weeks after any cytostatic therapy and 10 days after any other therapy. Neutrophil functions were investigated as follows: flow cytometric evaluation of whole blood phagocytosis of opsonized FITC-conjugated E. coli; whole blood chemiluminescence after stimulation with opsonized zymosan and evaluation by an automated, computer-assisted luminometer (LB 950, Berthold); and chemiluminescence and superoxide anion generation by purified neutrophils after f-MLP and PMA stimulation. Chemiluminescence and superoxide anion generation after f-MLP stimulation were found to be significantly lower than in normal subjects, whereas values within the normal ranges were registered after PMA stimulation. Phagocytosis-associated chemiluminescence was found to be impaired both by using zymosan opsonized with autologous plasma and zymosan opsonized with normal plasma, despite a normal phagocytic activity. These data show the presence in ET of a complex neutrophil dysfunction that may be related to an impaired signal transduction during both the phagocytic process and f-MLP stimulation.

Adult↗
PubMed1994

Evaluation of respiratory system resistance in mechanically ventilated patients: the role of the endotracheal tube.

OBJECTIVE: To investigate the role played by the endotracheal tube (ETT) in the correct evaluation of respiratory system mechanics with the end inflation occlusion method during constant flow controlled mechanical ventilation. SETTING: General ICU, university of Rome "La Sapienza". PATIENTS: 12 consecutive patients undergoing controlled mechanical ventilation. METHODS: We compared the values of minimal resistance of the respiratory system (i.e. airway resistance) (RRS min) obtained: i) subtracting the theoretical value of ETT resistance from the difference between P max and P1, measured on airway pressure tracings obtained from the distal end of the ETT; ii) directly measuring airway pressure 2 cm below the ETT, thus automatically excluding ETT resistance from the data. RESULTS. The values of RRS min obtained by measuring airway pressure below the ETT were significantly lower than those obtained by measuring airway pressure at the distal end of the ETT and subtracting the theoretical ETT resistance (4.5 +/- 2.8 versus 2.5 +/- 1.6 cm H2O/l/s, p < 0.01). CONCLUSION: When precise measurements of ohmic resistances are required in mechanically ventilated patients, the measurements must be obtained from airways pressure data obtained at tracheal level. The "in vivo" positioning of ETT significantly increases the airflow resistance of the ETT.

Acute Disease↗
PubMed1993

Assay of urinary 2,3-dinor-6-oxo prostaglandin F1 alpha by gas chromatography-tandem mass spectrometry.

Prostacyclin (PGI2), an important determinant of cardiovascular biology, is produced from arachidonic acid by endothelial cells. Measurement of its stable urinary metabolite, 2,3-dinor-6-oxo prostaglandin F1 alpha (PGI2-M), is the approach of choice to assess variations of the endogenous synthesis of PGI2 that occur in response to dietary, pharmacological and pathological alterations. We developed a relatively simple stable isotope dilution assay for PGI2-M which involves solid-phase extraction of 10 ml of urine with Chem Elut disposable columns, water/solvent partitioning from basic and acidic environments with ethyl acetate and methylene chloride, derivatization to 1-pentafluorobenzyl ester followed by TLC, methoximation and trimethylsilylation. Quantification was achieved, for the first time for PGI2-M, by capillary GC-electron capture negative ion MS-MS with a triple quadrupole mass spectrometer operated in the negative ion detection mode with methane as moderating gas. The mean inter-assay R.S.D., determined on 12 different urine samples, was 5.1 (range 0.4% to 10.5%). The excretion of PGI2-M in 34 healthy male subjects (age 26 to 57) was 156.2 +/- 65.2 (mean +/- S.D.) ng/24 h.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Ingestion of marine oil reduces excretion of 11-dehydrothromboxane B2, an index of intravascular production of thromboxane A2.

We evaluated the effect of anchovy oil supplementation on the endogenous production of thromboxane A2 by measuring the excretion of its stable metabolite, 11-dehydrothromboxane B2 (11-DTXB2), in 24-h urine. In a longitudinal study, 35 male volunteers consumed a controlled basal diet for two experimental periods lasting a total of 20 weeks. During period 1 (10 weeks) the diet was supplemented with placebo (PO) capsules (15 x 1 g/d) consisting of a blend of fats approaching the fatty acid profile of the basal diet. During period 2 the subjects received 15 x 1 g/d capsules of fish oil concentrate (FOC). PO and FOC capsules contained 1 mg alpha-tocopherol per gram of fat as antioxidant. A 38% reduction of 11-DTXB2 excretion was observed after 10 weeks of FOC supplementation (period 2, n-6/n-3 PUFA ratio = 2.3), compared to an identical period of PO supplementation (period 1, n-6/n-3 = 12.5), p = 0.0001. The 11-DTXB2 excretion reduction (delta) fits the quadratic equation delta = 136.0038-0.3178(tx1)-0.0002(tx1)2, (R2 = 0.8944), where tx1 is the excretion rate at the end of period 1. This finding supports the hypothesis that the antithrombotic effect of marine oil is mediated, at least in part, by diet-induced shifts in the eicosanoid system.

Diet↗
PubMed1992

13C and 31P NMR studies of glucose and 2-deoxyglucose metabolism in normal and enzyme-deficient human erythrocytes.

The flux of 13C-labeled glucose through the Embden-Meyerhof and pentose phosphate pathways was studied by 13C NMR in intact erythrocytes isolated from normal subjects or from patients suffering of glucose-6-phosphate dehydrogenase (G6PD, EC 1.1.1.49) deficiency. Similar rates of glucose catabolism and similar fluxes of the 13C-label into 2,3-bisphosphoglycerate and lactate were found, under basal conditions, in normal and in G6PD-deficient erythrocytes incubated in the presence of either [1-13C]- or D[6-13C]glucose. Exposure to oxidative stress by preincubation with tert-butylhydroperoxide induced in normal, but not in G6PD-deficient erythrocytes, a significant enhancement of glucose consumption, as well as a substantial reduction in 13C-label transfer from C1-glucose into lactate. It was also possible, by 31P NMR, to evaluate the conversion of 2-deoxyglucose to its phosphate-containing metabolites. The oxidation and subsequent decarboxylation of 2-deoxyglucose-6-phosphate was assessed in reconstituted systems and could subsequently be evidenced also in ethanolic extracts from normal (but not from G6PD-deficient) erythrocytes which had been exposed to oxidative stress. The results indicate that, in terms of glucose flux through the glycolytic pathway, there is little or no difference between normal and G6PD-deficient erythrocytes, regardless of previous exposure to oxidative stress. Faster consumption of either glucose or 2-deoxyglucose is induced, only in normal cells, by treatment with tert-butylhydroperoxide, essentially as a consequence of the activation of the pentose-phosphate pathway.

2,3-Diphosphoglycerate↗
PubMed1992

Arthroscopic treatment of flexion deformity after ACL reconstruction.

After anterior cruciate ligament (ACL) reconstruction, one frequent complication is the restriction of the range of motion and loss of extension. In addition to the presence of adhesions in the suprapatellar pouch, it is possible to detect two different pathological findings in the intercondylar notch: a misplacement of graft causing an intercondylar impingement, or the presence of hypertrophic tissue originating from the graft that blocks the last degrees of extension, causing an "anterior impingement." We reviewed 18 consecutive cases treated by arthroscopic release. All patients had knee range-of-motion restriction after an ACL procedure. The follow-up at 1 and at 6 months shows that good results have been obtained in cases of anterior impingement, whereas in cases of intercondylar impingement a restricted range of motion, especially of flexion, did remain. In all cases, after arthroscopic treatment the postoperative extension was between 5 and 10 degrees, but this deficit regressed after 6 months in 12 patients, whereas a dropout case was necessary in the remaining 6 patients.

Adolescent↗
PubMed1992

GC/MS/MS quantification of 11-dehydrothromboxane B2 in human urine.

A fully validated stable isotope dilution method for rapid quantification of 11-dehydrothromboxane B2 by gas chromatography/negative chemical ionization tandem mass spectrometry is reported. The interassay coefficient of variation was 1.3%. The relative recovery of synthetic, underivatized 11-dehydrothromboxane B2 added to urine was 84.6 +/- 2.5% (mean +/- SEM, N = 9). The equation of the regression plot correlating the amounts added and recovered was Y = 0.894X-0.23, with R = 0.9963. The late introduction of the pentafluorobenzyl moiety at C11 afforded distinct advantages in the cleanup stage of the assay and during the GC/MS analysis as well. The pair of daughter fragments at m/z 345 and 349 of the parent fragment ions at m/z 615 and 619 were monitored. Excretion values of 11-dehydrothromboxane B2 in 3 healthy male subjects were 975, 615 and 822 ng/24 h. Excretion was reduced to 751, 387 and 465 ng/24 h, respectively, after administration of a fish oil supplement (15 g/day) for 10 weeks.

Chromatography, High Pressure Liquid↗
PubMed1991

Osteoarthritis of the knee after ACL reconstruction.

One hundred and fourteen knees with deficiency of the anterior cruciate ligament (ACL) which had undergone reconstruction of the ligament using semitendinosus and gracilis were reviewed at a mean of 61 months after operation. Radiological and clinical evaluation was undertaken. A significant correlation was found between the number of meniscectomies performed in acute cases and those undertaken on the chronic knee. There was also significant correlation between meniscectomy and the Fairbank grading of degenerative changes seen on the radiographs. There was no correlation between the clinical results, residual laxity and the development of osteoarthritis. In ACL deficient knees with irreparable meniscal tears, or in which meniscectomy had been undertaken, the development of osteoarthritis seemed independent of the degree of stability, but in such knees with no meniscal tear or meniscal repair, reconstruction appeared to save the menisci and preserve the joint.

Adolescent↗
PubMed1991

Effect of fish oil supplementation on the excretion of the major metabolite of prostaglandin E in healthy male subjects.

We investigated the effect of fish oil supplementation on the synthesis of prostaglandin E (PGE) in vivo by measuring the excretion of its catabolite, PGE-M, in 24-hr urine by gas chromatography/mass spectrometry. Forty healthy male volunteers (24-57 years of age) consumed a controlled basal diet providing 40% of energy from fat (P/S ratio about 0.8:1), 130 mg/1000 kcal cholesterol, and a minimum of 22 mg/day of alpha-tocopherol (alpha-T), for three experimental periods lasting a total of 28 weeks. During period 1 (10 weeks) the diet was supplemented with placebo (PO) capsules (15 X 1 g/day) consisting of a blend of fats approaching the fatty acid profile of the basal diet. This was followed by a second 10-week period during which the subjects received 15 X 1 g/day capsules of fish oil concentrate (FOC). During period 3 (8 weeks) they continued the 15 g/day intake of FOC but received an additional 200 mg/day of alpha-T. PO and FOC capsules contained 1 mg alpha-T/g fat as antioxidant. A 14% reduction of PGE-M excretion was observed after 10 weeks of FOC supplementation (period 2), compared to an identical period of placebo supplementation (period 1), P = 0.009. PGE-M excretion during the last week of period 3 was not significantly different from that at the end of period 2. The reduction in PGE synthesis in response to the relatively high marine oil supplementation was large in many subjects participating in this study.

Adult↗
PubMed1991

PGE1 compared to PGE2/PGF2 alpha ratio as a marker for seminal fluid contamination of urine in studies of renal prostaglandin biosynthesis.

Occasional and unpredictable seminal plasma leakage (SPL) into the urinary system severely limits the usefulness of primary prostaglandin (PG) excretion rates as markers of renal synthesis in male subjects. Although reports to this effect appeared first some 10 years ago, no specific study has been done to define the magnitude of the problem, while several investigators persisted in the use of primary PG excretion rates, disregarding SPL as a confounding factor. We conducted a systematic study with a group of 5 healthy adult subjects who collected 24-h urine with an average frequency of one collection every other week for a total of 20 weeks. 35% of the urine collected contained seminal plasma. It is imperative to be able to disqualify compromised urine specimens in biological studies. With this objective in mind, we developed a method to identify contaminated samples based on the presence of PGE1. This is a major prostanoid in seminal plasma but is normally absent in 'clear' urine.

Adult↗
PubMed1991

Third-degree lesions of the external compartment of the ankle: results of conservative treatment.

Ankle sprains are one of the most common lesions of the musculo-skeletal system. In some sports they are the most common reason that athletes seek medical care. For this reason many publications are dedicated to this subject, and specifically to the treatment of lesions of the external compartment, which account for about 85% of all ligamentous lesions of the ankle (O'Donoghue, 1958). The treatment of these lesions is very controversial. Some orthopedists propose early surgical treatment to restore normal healing with minimal functional lengthening. Others favor conservative treatment, while still others recommend functional treatment with the objective of accelerating the recovery of proprioceptive reflexes affected by the ligamentous lesion as well as stimulating healing by movement. The authors' diagnostic and therapeutic approach to lesions of the external compartment of the ankle is explained with special reference to lesions in athletes, who must be guaranteed perfect joint stability in order to tolerate the intense stress of sports activity without danger of relapse.

Adolescent↗
PubMed1990

Modification of prostaglandin metabolism in vivo by long-chain omega-3 polyunsaturates.

In a pilot study conducted with a healthy male volunteer we determined that short-term dietary supplementation with fish oil markedly suppresses the systemic production of prostaglandin E (P = 0.04). This biochemical effect is observable after an incubation period of several days. The potential consequences of a reduced PGE synthetic rate on renal function, immune system and vascular dynamics, must be considered in the overall evaluation of the safety of fish oil supplements.

Fatty Acids, Omega-3↗