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Biomedical subjects

G Garibotto

Publications and source records attributed to G Garibotto.

87 records · Page 5Linked to original sources
PubMedDate not supplied

Study of bioassayable somatomedin on renal artery and vein.

Somatomedin was measured by rat bioassay in samples obtained from renal artery and vein, in order to study the role of this organ in the production of somatomedin activity. The results showed a significant difference, with an increase of the activity in the venous samples. According to the data reported in the literature with bioassay (low values) and radioreceptor assay (normal or high values) in nephropathic subjects, our results seem to suggest that the kidney mainly inactivates a specific somatomedin inhibitor.

Adolescent↗
PubMedDate not supplied

Renal metabolism of amino acids in early insulin-dependent diabetes mellitus.

Renal metabolism of amino acids (AAs) was evaluated in 5 patients with early IDDM, and in 7 controls (C) in the basal state for 80 minutes after the ingestion of an AA mixture simulating an animal protein meal. Insulin was withdrawn 20 hours before the study. Renal metabolism of AAs was evaluated by the arterial-venous difference technique. In the basal state in IDDM, as in C, the kidney takes up large amounts of a few nonessential AAs (NEAAs): it releases many NEAAs and a few essential AAs (EAAs). After AA ingestion in C, renal extraction of most EAAs, mainly BCAAs, Lys, and Thr, occurs; Pro extraction also increases and a significant uptake of Gly, Glu, Asp, Orn, and Tyr takes place. EAA extraction accounts for 30-40% of total AA uptake. In IDDM, after AA ingestion, a) renal uptake of total AAs is significantly lower, owing mainly to a markedly lower uptake of BCAAs, Lys, and also of Pro, Orn, and Ala; b) renal EAA uptake accounts for less than 20% of total AA extraction. These results indicate that in IDDM postprandial renal N repletion is impaired and unbalanced.

Adult↗
PubMedDate not supplied

Amino acid metabolism, substrate availability and the control of protein dynamics in the human kidney.

The mechanisms controlling protein metabolism in the human kidney are not well understood. During adult life, kidney protein content and the size of the kidney remain fairly constant, indicating that protein synthesis and degradation within the kidney are tightly regulated. However, kidney protein turnover may change in response to stimuli such as alterations in substrate availability, hormones or growth factors, acid-base balance, renal work or renal injury with a progressive decrease in the number of nephrons. These factors have been evaluated mainly in animals, in vitro or in vivo. Amino acids, the kidneys substrates for protein synthesis, are provided by several routes. Like in other organs, amino acids can reach the kidney cells through the arterial blood flow. However, they may also come from the degradation of reabsorbed low-molecular weight proteins filtered by the glomerulus. The human kidney has high rates of protein turnover and leucine oxidation. The magnitude of the protein turnover across the human kidney suggests that the protein dynamics is partly determined by intrarenal protein catabolism. As evaluated by a steady-state leucine multiple compartment analysis, kidney protein synthesis is dependent to a similar extent on intrarenal generation of amino acids from protein breakdown and from amino acids taken up from the arterial blood. Kidney mass may therefore depend not only on the availability of free amino acids, but also on filtered proteins which are degraded within the kidney. Future studies could define the mechanisms, metabolic pathways and mediators influencing kidney protein turnover in humans, with a view to better comprehension of the mechanisms of disease.

Amino Acids↗
PubMedDate not supplied

[Acute effects of peritoneal dialysis on muscle protein turnover].

BACKGROUND: Despite continuing glucose absorption and stimulation of insulin secretion, wasting is common in patients with chronic renal failure (CRF) treated with peritoneal dialysis. METHODS: To evaluate if peritoneal dialysis per se has any effect(s) on muscle protein turnover we employed the forearm perfusion method associated with the kinetics of 3H-phenylalanine in seventeen patients with CRF in the basal state and: a) during the systemic hyperinsulinemia associated with peritoneal dialysis (6 patients) (200-240 min); b) during locally-induced hyperinsulinemia, without systemic effects on aminoacid (AA) availability (6 patients) (80-120 min); c) in time-controls (5 patients) (80-240 min). RESULTS: Peritoneal dialysis and local infusion of insulin in the brachial artery (0.01 mU/min/kg) induced a similar degree of systemic or local, moderate hyperinsulinemia (19+/-4 e 21+/-3 microU/ml, respectively). During both protocols an insulin-related inhibition of muscle protein degradation occurred; however peritoneal dialysis caused a 20% decrease in forearm phenylalanine rate of disposal (an index of muscle protein synthesis), which correlated with the decline of arterial BCAA and potassium, which were removed via the peritoneal fluid. Furthermore, a persistent negative net phenylalanine and AA balance across the forearm was observed during peritoneal dialysis, while the negative basal net phenylalanine and AA balance was reversed to a positive or neutral one during local hyperinsulinemia. CONCLUSIONS: We conclude that in CRF patients even a modest elevation in local insulin levels is followed by an anabolic muscle response, while the same effect is not observed during the systemic hyperinsulinemia associated with substrate removal which occurs during peritoneal dialysis. In this setting the antiproteolytic effect of hyperinsulinemia is offset by a decrease in muscle protein synthesis which is accounted for by a decrease in AA availability. Our data indicate that protein metabolism during peritoneal dialysis is characterized not only by decreased, but also less efficient, turnover rates.

Amino Acids↗
PubMedDate not supplied

[Complications of the nephrotic syndrome].

We described the case of a 27-year-old man presenting pulmonary embolism and hyperlipidaemia. Subsequent investigation revealed that he was affected by renal vein thrombosis and nephrotic syndrome due to membranous glomeruloephritis. Nephrotic syndrome complications are numerous and may represent the first sign of the syndrome. Among these complications we find thromboembolism, infections, negative nitrogen balance and renal failure. There are very few prognostic indicators that enable the prediction of nephrotic syndrome complications. Recent advances in the understanding of alterations in the metabolism of circulating and somatic proteins associated with proteinuria and hypooncotic condition have led to new insights into the pathophysiologic processes associated with the syndrome.

Adult↗
PubMedDate not supplied

[Metabolic acidosis in patients with chronic kidney diseases: why and when to treat it?].

Metabolic acidosis is a common complication in patients with advanced chronic renal diseases and dialytic treatments are unable to correct it completely. In hemodialysis (HD) patients, severe metabolic acidosis is associated with an increased risk of death. Evidence from several experimental studies suggests that even mild metabolic acidosis is associated with systemic effects. Acidosis is implicated in endocrine changes and has negative repercussions on bone and protein metabolism. In addition, recent observations suggest that acidosis triggers inflammation and accelerates the progression of chronic kidney diseases. As a contradictory finding, acidosis can reduce circulating leptin. Clinical studies on the nutritional effects of metabolic acidosis correction have shown mildly favorable effects. Taking into account the systemic effects of metabolic acidosis it is suggested that even mild metabolic acidosis is corrected. However, the new findings concerning the systemic effects of acidosis must be evaluated in controlled trials.

Acidosis↗
PubMedDate not supplied

[Census 2004 of the Italian Renal and Dialysis Units--Piemonte, Liguria and Valle d'Aosta].

The Italian Society of Nephrology (SIN) promoted a national survey in order to obtain detailed information from all Renal and/or Dialysis Units using the on-line questionnaire (158 items) regarding structural and technological resources, medical workforce organisation and activity features. The purposes of this initiative were to obtain regional benchmarks as references for renal units and to describe the current Italian renal network in order to plan further interventions for the next 5 years. In this paper data of the first three Italian Regions (Piemonte, Liguria and Valle d'Aosta) which completed the survey (100% of the units) are reported. Main findings in the 3 Regions. A) Epidemiology: prevalence of dialysis patients = 709, 720, 787 pmp (per million population); prevalence of transplanted patients = 325, 387, 279 pmp; incidence of dialysis patients = 166, 191, 156 pmp; gross mortality of dialysis patients = 13.7, 15.0, 13.0%; distribution of vascular access in prevalent dialysis patients: arteriovenous fistula = 74, 83, 76%, central venous catheter = 18, 12, 15%, vascular graft = 8, 5, 9%. B) Structural resources: hospital's number of beds = 49, 72, 49 pmp, dialysis places = 166, 158, 164 pmp. C) Personnel resources: renal physicians = 44, 47, 41 pmp, renal nurses = 186, 194, 205 pmp; each renal physician takes care of 16, 15, 19 dialysis patients and each renal nurse cares for 3.8, 3.7, 3.8 dialysis patients. D) Activity: admission to hospital = 1507, 2392, 1606 pmp, renal biopsies = 109, 133, 57 pmp. Despite discrepancies in population density in the three Regions, most indexes are surprisingly similar and show the satisfactory level of renal care attained in the Northwestern Italian area. Further improvements in health care management can be predicted as a consequence of a direct comparison between needs and results in the various Regions of the Country.

Censuses↗
PubMedDate not supplied

Three-dimensional neuroanatomic images in CT-guided stereotaxic neurosurgery.

A technique is described for three-dimensional reconstruction of human diencephalic structures based on information contained in a widely used stereotaxic brain atlas. Various methods of graphically representing the obtained diencephalic volumes are discussed and examples are given. The anatomic information contained in the computerized atlas can be implemented with computed tomography performed under stereotaxic conditions. Volume data provided by the tomograms are used for three-dimensional "stretching" of the volumes presented in the atlas. Improved accuracy in identifying "invisible" diencephalic targets in functional stereotaxic neurosurgery is expected to result from this new technique.

Brain↗