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Biomedical subjects

V Bocci

Publications and source records attributed to V Bocci.

At least 109 records · Page 6Linked to original sources
PubMed1981

Renal filtration, absorption and catabolism of human alpha interferon.

The renal handling of human interferon-alpha has been evaluated by using an isolated and perfused rabbit kidney. IFN-alpha disappears from plasma with a t1/2 of 81 min and the fractional turnover rate is 0.84%/min. About 47 molecules of IFN-alpha are filtrated with 100 molecules of creatinine but most of the IFN is absorbed by tubular cells. This is the first report showing that human IFN-alpha is filtrated by the kidney, largely absorbed, most probably catabolized within tubular epithelium and excreted in negligible amounts with the urine.

Animals↗
PubMed1981

Renal metabolism of rabbit serum infection.

Three different approaches have been used to evaluate the catabolism of rabbit serum interferon (IFN) by the kidneys. Firstly, in normal rabbits the disappearance of exogenous IFN from plasma was very rapid, whereas it was significantly slower after bilateral nephrectomy. Secondly, the IFN level in arterial blood was always higher than in renal venous blood: the mean renal extraction rate of IFN in the rabbit, with a renal plasma flow of 9 ml/min, was about 1 ml/min. Thirdly, a selective and reversible tubular damage induced by maleate before intravenous administration of IFN significantly inhibited luminal uptake of IFN and markedly increases the interferonuria. All of these results support the view that the kidneys have a preponderant role in IFN filtration, catabolism and excretion.

Animals↗
PubMed1980

Poor performance of the isolated rabbit kidney perfused with free-cell media and whole blood.

All of these results indicate that the isolated rabbit kidney, perfused either with free-cell media or with whole blood, shows marked functional deficiencies and cannot be considered a reliable preparation. The former media do not induce vasoconstriction but are unable to insure a correct cations reabsorption, while the latter causes intense renal vasospasm and clogging of the glomerular circulation indicated by high arterial pressure and hematuria. On the basis of these observations it appears indispensable to use a perfusion medium capable of eliciting renal autoregulation but deprived of blood elements such as platelets and leukocytes that may be either directly or indirectly responsible for the glomerular clogging. This problem is considered in the following communication.

Animals↗
PubMed1980

Studies of factors regulating the ageing of human erythrocytes--III. Metabolism and fate of erythrocytic vesicles.

1. Ageing erythrocytes release vesicles the metabolism of which is unknown. 2. Human and rat erythrocytic vesicles labelled with 51Cr and injected into rats, disappear very rapidly from the circulation with half-lives from 2 to 8 min. 3. Their lifetime resembles that of liposomes encapsulating [51Cr]haemoglobin (Hb) and in both cases, liver and spleen take up considerable amounts of radioactivity. 4. These results indicate, for the first time, that vesicles released from erythrocytes are cleared at very fast rates from the circulation and suggest that this may be the reason for the absence of vesicles in the plasma in vivo.

Animals↗
PubMed1980

Is interferon produced in physiologic conditions?

On the basis of a number of physiologic, microbiologic and immunologic data it is possible to formulate the hypothesis that interferon is produced continuously in health by the gut-and bronchial-associated lymphoid tissue and, although several anatomic areas are involved, interferon synthesis is supposed to be restricted to the mucosal portals of entry. The interferon physiologic response is characterized by prevalent production of type II interferon and by its localized release, function and catabolism. However, the consequences of this response may have far-reaching biological importance because production of IF, though localized, can activate fundamental defence systems throughout life. It is furthermore postulated that the progressive decline of the interferon physiologic response may be one important event favouring the insurgence of tumours and autoimmune diseases in ageing.

Animals↗
PubMed1979

Studies of factors regulating the ageing of human erythrocytes. II. Metabolic depletion of erythrocytes is not accompanied by a decrease of their sialic acid content during blood bank storage.

Erythrocytes from human blood stored at 5 degrees C in anticoagulant-preservative solutions are considered, after a period from 21 to 24 days, unsuitable for transfusion. The nonviability of the cells appears due to metabolic impairment accompanied by a change of the biophysical properties of the cell but surprisingly not to a decrease of sialic acid of the membrane. The absence of proteolysis can be attributed to calcium chelation and to the stable levels of plasma protease inhibitors throughout the storage period. In fact, when erythrocytes are incubated for several days at 5 degrees C in protein-free media, release of sialopeptides from the membrane increases slowly and steadily, particularly if the medium is without glucose and adenine but contains divalent cations. Moreover, this phenomenon is strikingly amplified when incubation in protein-free media is carried out at 37 degrees C and once the ATP level has fallen below 5% of its initial value.

Adenine↗
PubMed1977

The role of sialic acid in determining the survival of circulating interferon.

Rabbit interferon has been extensively desialytated and its metabolic behaviour has been evaluated in the rabbit. The half-life of asialointerferon is significantly shorter than the native interferon and its urinary excretion becomes negligible. Moreover the rapid uptake of asialointerferon by the isolated and perfused rabbit liver, suggests a hitherto unsuspected catobolic pathway for this glycoprotein.

Animals↗
PubMed1977

Metabolism of interferon: hepatic clearance of native and desialylated interferon.

The effect of removal of sialic acid on the survival of rabbit serum and urinary interferon (IF) has been investigated in isolate, perfused rabbit liver preparations. In contrast with native IF, which may be already partially desialylated. IF freed of 80 to 90% of its sialic acid was rapidly cleared from the perfusate of normal livers, or livers pre-treated with actinomycin D. The results suggest that the mechanism of IF catabolism by the liver is similar to that reported for several other circulating glycoproteins.

Animals↗