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Biomedical subjects

C Canavese

Publications and source records attributed to C Canavese.

At least 73 records · Page 4Linked to original sources
PubMed1989

Prevention and treatment of aluminum overload in uremic patients: long-term results.

The authors evaluate the efficacy of a protocol of prevention and treatment of aluminum (Al) overload in RDT patients during a 7-year period (from 1981, 164 patients, to 1987, 161 patients). Al in dialysate solutions was always less than 25 micrograms/l. Baseline Al levels greater than 100 micrograms/l were found in 22% of patients in 1981 but in none in 1987, while the percentage of values less than 60 micrograms/l increased from 55 to 91%. DFO tests were positive in 54% and 7% of cases in 1981 and 1987, respectively. A clinical diagnosis of Al intoxication was performed in 6 patients in 1981, and no further cases were diagnosed later. DFO treatment (50 mg/kg once a week) was employed preventively in 31 patients owing to positive DFO-tests, and in the 6 Al-intoxicated patients therapeutically. In the former patients none developed clinical intoxication. In the latter group clinical improvement was only temporary in the three parathyroidectomized patients. Al hydroxide [Al(OH)3] as a phosphate binder was tapered off in 1981 and substituted by Al-free chelants. In 1987, 66% of patients were given CaCO3 or Mg (OH)2 alone or in association, while 34% still needed Al(OH)3, although at low dosages (less than 2 g/day). The conclusion is that such a protocol is able to prevent and to treat cases of Al intoxication, albeit only partially.

Adult↗
PubMed1989

Pregnancy-related acute renal failure.

From 1958 to 1987, 81 cases of pregnancy-related acute renal failure (PR-ARF) were observed (9% of the total number of acute renal failure [ARF] needing dialysis). In the three successive ten-year periods (1958-67, 1968-77, 1978-87) the incidence of PR-ARF fell from 43% to 2.8% with respect to the total number of ARF, and from 1/3,000 to 1/15,000 with respect to the total number of pregnancies. Maternal mortality was high (32%), with 5 cases of death in the last ten years. Irreversible renal damage was recorded in 11.6% of PR-ARF, and, in particular, in 26.3% of cases in preeclampsia-eclampsia (PE-E). Worse maternal and renal prognosis occurred in PE-E complicated by abruptio placentae. Neither disseminated intravascular coagulation (DIC), microangiopathic hemolytic anemia nor prostacyclin imbalance were significantly related to the severity of renal damage. Heparin therapy did not modify DIC evolution and renal outcome and was aggravated by severe hemorrhagic complications. In conclusion, PR-ARF has become a rare, but still critical occurrence, and the most effective measures would be a program of careful prevention.

Acute Kidney Injury↗
PubMed1988

The role of intravascular coagulation in pregnancy related acute renal failure.

Pregnancy-related acute renal failure (ARF) can include reversible tubular necrosis as well as irreversible cortical necrosis. Though pathogenetic mechanism are not fully understood, disseminated intravascular coagulation (DIC) probably plays a primary role. We report 25 cases of pregnancy-related ARF: 13 were associated with preeclampsia or eclampsia and 12 with obstetric complications. The following parameters were studied: partial thromboplastin, prothrombin and thrombin time, fibrinogen, anti-thrombin III and FDP levels, platelet count, whole blood clot lysis time and area, fragmented red cells (schistocytes) in the blood smear, hemoglobin, aptoglobin and LDH concentrations. DIC was scored in arbitrary units ranging from 12 to 36 and related to the clinical picture, renal outcome and the treatment employed. Five patients had irreversible renal damage, while 19 recovered fully; one patient died and no renal histology was available. The DIC score did not seem to have a significant relation to the severity of renal damage.

Acute Kidney Injury↗
PubMed1988

The case for oxygen free radicals in the pathogenesis of ischemic acute renal failure.

One of the more glaring paradoxes of ischemic acute renal failure is that such injury appears to be worse in the kidney as opposed to other organs, even though the kidney is the best oxygenated. An answer can be deduced from the anatomical and physiological background, together with a reappraisal of the role of medullary vascular damage and recent evidence of the importance of the postischemic component of ischemic injury, which is mediated by oxygen free radicals. As far as oxygenation is concerned, the kidney's Achilles heel is the tubules of the outer strip of the outer medulla, which are also those that have the most metabolic activity. It is here that ischemic injury begins, and is maintained and exacerbated in the postischemic stage by the free radicals. These are produced by the kidney in large quantities, since it has all the necessary chemical ingredients available. It is therefore readily understandable why the kidney, being the best oxygenated organ, is so sensitive to an ischemic insult, since the damage caused in the postischemic stage is increased the greater the amount of oxygen brought in by reperfusion.

Acute Kidney Injury↗
PubMed1987

Acute renal failure in preeclampsia-eclampsia.

Acute renal failure (ARF) is regarded as relatively uncommon in preeclampsia-eclampsia (PE-E) and, in any event, of moderate degree or reversible. Cortical necrosis is reported as rare, even in fatal cases. Little light has as yet been shed on the mechanisms responsible for ARF in PE-E. This paper describes 17 cases observed over the last 15 years, in which cortical necrosis (3 histological and 2 clinical diagnoses) was relatively frequent (29.4%). The severity of renal impairment did not appear to be related to chronological age, parity, period of pregnancy in which PE-E commenced and its duration prior to delivery, presence of frank eclamptic crises or the concomitance of earlier vascular or renal disease (p greater than 0.05). The superimposition of abruptio placentae (AP) was the only clinical factor significantly correlated with cortical necrosis (p greater than 0.05). The association PE-E + AP seems to be a particularly unfavorable prognostic sign for the kidney owing to the contribution of additional damage mechanisms (vasospasm, disseminated intravascular coagulation, hemorrhagic shock) furnished by AP, while PE-E itself prepares the ground for AP. The fact that PE-E is difficult to diagnose when AP is the onset symptom may be responsible for the underestimation of its contribution towards the induction of severe renal damage.

Abruptio Placentae↗
PubMed1987

Oxygen free radicals in nephrology.

For living creatures with an aerobic metabolism, the univalent reduction of oxygen can lead to formation within the cell of intermediate products with marked chemical instability and strong potential toxicity. These are the free radicals (FR) superoxide and hydroxyl, hydrogen peroxide and the singlet 1O2. Their toxicity is primarily expressed through the peroxidation of membrane lipids, resulting in mitochondrial, lysosomal and parietal damage. It is enhanced by the presence of metals in trace amounts. Imbalance between the production of FR and the availability of FR scavengers (superoxide dismutase, catalase, glutathione peroxidase, etc.) may underlie different human pathologies. FR have been thought to play a part in inflammation, the aging process, carcinomatous transformations, damage due to recirculation and autoimmune diseases. As far as the kidney is concerned, the intervention of FR has been demonstrated or can be postulated in various contexts in the light of what has been observed in other pathologies: immunological nephritis, toxic nephropathies, microthrombotic and microangiopathic processes, damage caused by post-ischemic reflow, and problems in the preservation and rejection of transplants. FR have also been incriminated in lung lesions following intradialytic leukostasis and some aspects of toxicity ascribable to uremia. Subject to the precautions imposed by the need for theoretical, experimental and clinical verification, FR biochemistry offers new keys to the interpretation of a variety of kidney pathologies and opens up new prospects for treatment, both through a better understanding of the mechanism of action of drugs already known and employed, and with regard to the practical possibility of using alternative or combined forms of therapy.

Animals↗
PubMed1986

Postpartum acute renal failure in a drug addict.

Renal diseases occur in intravenous drug abusers, especially heroin addicts, in the form of interstitial nephritis, nephrotic syndrome or acute renal failure due to rhabdomyolysis. We report a case of acute renal failure not ascribable to rhabdomyolysis nor to the main pathogenetic mechanisms of pregnancy-related acute renal failure in a pregnant heroin addict woman after vaginal delivery following uncomplicated pregnancy. Drug-related immunological abnormalities and microcirculatory distress may be involved.

Acute Kidney Injury↗
PubMed1986

Clinical and therapeutic correlations in consumption coagulopathy of obstetric acute renal failure.

Heparin has been proposed following the supposed role of disseminated intravascular coagulation (DIC) in the pathologies associated with the consumption coagulopathies such as obstetric acute renal failure (ARF), whilst antifibrinolytic agents could be advocated to stop a simultaneous triggered fibrinolysis. Out of 26 obstetric ARF DIC may be demonstrated in 10 and supposed in 6 patients who developed severe post-partum uterine bleeding. Therapeutic schedules employing heparin or antifibrinolytic agents early post-partum do not seem to change either the behaviour of laboratory parameters (showing a DIC partial resolution within 48 hours), or heavy bleeding in respect to the patients treated with supportive therapies alone. Furthermore, heparin administered during the following days does not seem to be a crucial factor in the renal recovery, and is often followed by severe haemorrhagic complications. Fresh frozen plasma after aprotinin is able to stop bleeding in the presence of persisting signs of consumption without damaging renal recovery.

Acute Kidney Injury↗
PubMed1986

Heparin transfer across the rabbit peritoneal membrane.

Variable quantities of heparin have been proposed to avoid intraperitoneal clotting during peritoneal dialysis without the risk of systemic effects, because heparin is presumed to be incapable of passing through the peritoneal membrane. This study set out to verify this assumption by using labeled heparin in experimental dialysis in 7 New Zealand white rabbits. Heparin was labeled with 99mTc. Labeling quality, assessed by two chromatographic checks, showed less than 5% of free pertechnetate. Chromatographic determinations showed more than 95 and 80% of labeled heparin in inflow and outflow dialysates and in blood samples respectively. Following sodium thiopental anesthesia, animals underwent three protocols: a single 15 min cycle of time diffusion with heparin 500 U/l (A), 6 successive 15 min cycles with heparin 500 U/l (B), and a single 3 h cycle with heparin 2,500 U/l (C). Labeled heparin was found in blood organs and urine in variable percentages. The total amount of recovered radioactivity ranged from 1.5% (A) to 20% (C) of that introduced. It may be concluded that heparin passes through the peritoneum according to some law dependent on the amount used and the diffusion time.

Animals↗
PubMed1986

Acute renal failure in obstetric complications.

Early postpartum disseminated intravascular coagulation (DIC) was demonstrated by serial coagulation studies in 10 cases of acute renal failure (ARF) following obstetric complications (6 abruptio placentae, 3 retained placental fragments, 1 prolonged intrauterine fetal death). DIC abated within 48 hours irrespective of the therapeutic schedules employed. Renal damage was evidenced by a varying number of days of oligoanuric (6 cases) or polyuric (4 cases) ARF which always required dialytic treatment. Full renal recovery occurred in 9 cases. One patient died and no histological studies were performed. Renal damage seemed to correlate less with DIC than with the degree of anemia and shock.

Abruptio Placentae↗
PubMed1986

Hypervitaminosis B12 in maintenance hemodialysis patients receiving massive supplementation of vitamin B12.

We have administered routinely a multivitamin preparation containing a megadose of B12 to 106 hemodialysis patients after dialysis treatments. We found that these patients had very high levels of serum vitamin B12 which returned to original values only after a period of three years after stopping the vitamin. Discontinuing therapy had no effect on hemoglobin, mean erythrocyte corpuscular volume, or motor nerve conduction velocity. It is not known whether maintaining a prolonged high level of vitamin B12 is harmful. However, animal and epidemiologic studies have suggested that both cobalamin and cobalt may be potentially toxic. In view of the absence of demonstrable benefit and the possible risk of toxicity, we believe that the use of such megadose vitamin compounds in dialysis patients should be re-evaluated.

Adult↗