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Biomedical subjects

Q Maggiore

Publications and source records attributed to Q Maggiore.

At least 55 records · Page 3Linked to original sources
PubMed1987

Plasma met-enkephalin and leu-enkephalin in chronic renal failure.

Plasma met-enkephalin and leu-enkephalin has been measured in a group of 28 patients with chronic renal failure, to discover whether these opioids are affected by standard haemodialysis and haemofiltration. Met-enkephalin was markedly higher (P less than 0.001) in uraemic patients than in a group of 13 normal subjects, and was directly related to plasma creatinine (r = 0.60; P less than 0.01) and to plasma urea (r = 0.36; P = 0.06). In contrast, leu-enkephalin was suppressed in uraemic patients (P less than 0.001). Met-enkephalin fell slightly but significantly (P less than 0.02) after both haemodialysis and haemofiltration; however, on average it remained at concentrations four times higher than normal. No changes in plasma leu-enkephalin were observed after haemodialysis and haemofiltration. The cause(s) of the altered plasma concentrations of these opioid substances remains to be clarified.

Adult↗
PubMed1986

Parasympathetic function in haemodialysis patients.

The long-term course of the parasympathetic neuropathy in patients with chronic renal failure maintained on haemodialysis was investigated. Well-established tests of parasympathetic function (deep breathing test, atropine test) were performed in 45 patients who had been dialysed for periods ranging from 1 to 12 years and in 34 normal subjects. The responses to these tests were clearly compromised in dialysis patients but there was no relationship between duration of haemodialysis treatment and results of parasympathetic tests. In the 13 patients who were re-evaluated after an interval of 4 years there was no evidence of progression of the parasympathetic neuropathy. The results suggest that chronic haemodialysis treatment halts parasympathetic damage in patients with chronic renal failure.

Adult↗
PubMed1986

Effect of ultrafiltration on plasma concentrations of atrial natriuretic peptide in haemodialysis patients.

We have investigated the influence of body fluid volume status on plasma levels of immunoreactive atrial natriuretic peptide (irANP) in eight uraemic patients on chronic haemodialysis, including two diabetics with severely impaired reflex control of the heart. IrANP was significantly higher in volume-expanded uraemic patients (36 +/- 16 pg/ml) than in a group of seven age and sex-matched normal subjects (14 +/- 2 pg/ml), and fell consistently, approaching the normal range after the removal of 2.0-4.3 litres of isotonic plasma ultrafiltrate (by isolated ultrafiltration). Plasma levels of the hormone were strictly related to right atrial pressure. The irANP response to ultrafiltration in the two diabetics was similar to that of the other uraemic patients. The results suggest that the elevated irANP levels found in volume-expanded uraemic patients depend largely on fluid overload per se. The preserved irANP response to ultrafiltration of the two diabetics with severe autonomic neuropathy indicates that in chronic renal failure irANP secretion may be regulated independently from autonomic influences.

Adult↗
PubMed1985

Effect of naloxone on the defective autonomic control of heart rate in uraemic patients.

The role of endogenous opioids on the reflex cardiovascular control of chronic uraemic patients was investigated. The opiate antagonist naloxone administered intravenously caused a significant increase in the abnormal Valsalva manoeuvre ratio in nine chronic uraemic patients, but it had no effect in six diabetic patients with normal renal function, whose response to the Valsalva manoeuvre was similar to that of chronic uraemic patients. Naloxone had no effect in eight normal subjects. The increase in the Valsalva ratio observed in uraemic patients was due to restoration of the parasympathetically mediated reflex bradycardia of the release phase of the manoeuvre. Naloxone did not modify supine and standing blood pressure and heart rate in any group. Endogenous opioids may be involved in the defective autonomic control of heart rate in uraemic patients.

Adult↗
PubMed1985

Hyperchloraemia: a non-specific finding in chronic renal failure.

To determine the prevalence of hyperchloraemia (plasma chloride concentration of 107 mmol/l or above) in chronic renal failure (CRF), we retrospectively analysed the acid-base and electrolyte status of 102 Italian and 53 English patients with impaired renal function. Hyperchloraemia was a frequent finding at all stages of CRF with a prevalence ranging from 30 to 50%. It was common both in tubulointerstitial nephropathies (45%) and chronic glomerulonephritis (39%). Hyperchloraemic patients were more acidotic than the normochloraemic.

Acid-Base Equilibrium↗
PubMed1985

The effect of dialysate temperature on haemodialysis leucopenia.

We assessed the influence of dialysate temperature on intra-dialytic leucopenia. Lowering dialysate temperature from 38 degrees C to 20.5 degrees C caused a decrease in the dialysis associated white blood cell reduction from 82 +/- 6 per cent to 32 +/- 19 per cent. The degree of leucopenia bore a highly significant relationship with dialyser blood temperature suggesting that a further lowering of blood temperature (to about 20 degrees C) would almost entirely prevent intra-dialytic leucopenia.

Adult↗
PubMed1985

The role of endogenous opioids in the baroreflex dysfunction of dialysis patients.

We studied the effect of the opiate antagonist naloxone on the response to Valsalva manoeuvre in nine dialysis patients, in six diabetics with normal renal function whose response to Valsalva manoeuvre was similar to that of dialysis patients and in eight healthy subjects. Naloxone caused a progressive increase in the subnormal Valsalva ratio in dialysis patients but it did not cause any change in diabetics nor in healthy subjects. The increase in Valsalva ratio observed in dialysis patients was due to restoration of the parasympathetically mediated reflex bradycardia of the release phase of the manoeuvre. Endogenous opioids may be responsible for the baroreflex dysfunction of dialysis patients.

Adult↗
PubMed1985

Influence of blood temperature on vascular stability during hemodialysis and isolated ultrafiltration.

We tested the hypothesis that differing temperature (T) changes in extracorporeal blood circuit might partly account for the difference in vascular stability (VS) between isolated ultrafiltration (UF) and simultaneous UF-hemodialysis (HD). The study was carried out in 6 patients who presented frequent episodes of symptomatic hypotension during the routine dialytic sessions. During simultaneous UF-HD with dialysate T set at 37.5 degrees C (standard HD), blood reentered the patients with a T of about 2 degrees C higher, whereas during isolated UF (standard UF) 2 degrees C lower, than at its exit. These extracorporeal blood T changes were reciprocated by warming the venous line in isolated UF (warm UF) and by setting the dialysate at 34.5 degrees C in simultaneous UF-HD (cold HD). During warm UF mean arterial pressure (MAP) fell and heart rate (HR) increased nearly as much as during standard HD. Vice versa, during cold HD MAP and HR remained nearly as stable as during standard UF. It is concluded that the T changes in blood flowing through the extracorporeal circuit largely account for the differing VS between isolated UF and simultaneous UF-HD.

Adult↗
PubMed1985

Long term effects of cryoapheresis and cytostatic treatment in essential mixed cryoglobulinemia.

We studied the effects of cryoapheresis combined with different immunosuppressive treatments on the course of the glomerulonephritis of essential mixed cryoglobulinemia. The study was carried out on 11 patients. The effects of immunosuppressive treatments on cryoglobulin rebound after cryoapheresis varied widely. In those responding with sustained reduction in serum cryoglobulin levels, creatinine clearance increased, an effect that lasted several years in 4 patients. In one patient cryoglobulin disappeared, with almost fully recovery of renal function and normalization of blood pressure. One patient died of acute liver failure shortly after the first observation and another entered regular dialysis treatment. All the other patients are still alive after follow-up of 2-9 years. These results compare favourably with those reported by other investigators and suggest that cryoapheresis and cytostatic drugs are beneficial for glomerulonephritis associated with essential mixed cryoglobulinemia.

Adult↗
PubMed1983

The value of ultrasound as a screening procedure for urological disorders in renal failure.

Renal ultrasound was evaluated as a screening procedure for urological conditions (hydronephrosis or space-occupying lesions) in 175 patients (316 kidneys) with renal failure. The final diagnosis of renal disease was based on excretory urography, ascending or translumbar pyelography, open surgical findings, clinical and laboratory test results or renal biopsies. Ultrasonic images suggestive of renal disease requiring surgery were obtained in 83 kidneys and subsequently confirmed in 67. There were 16 falsely positive and 2 falsely negative results. Assuming a 22 per cent prevalence of renal disease requiring surgery in the azotemic population, Bayes' theorem predicts that an abnormal ultrasonic test will increase the probability of surgery in a patient with renal failure from 0.22 to 0.81, while a negative test will reduce the probability from 0.22 to 0.013. Renal ultrasound is a highly effective method to screen for patients with renal failure who require contrast studies. With this means the risks and cost of contrast investigations can be reduced markedly.

Adolescent↗
PubMed1983

Glomerular deposits of rheumatoid factor in glomerulonephritis.

One hundred and forty-four kidney biopsy specimens with various forms of glomerulonephritis were studied to assess the presence of Rheumatoid Factor (RF) deposits. RF deposits were found in 21 specimens: six with acute post-streptococcal glomerulonephritis, two with crescentic glomerulonephritis, four with lupus nephritis, eight with essential mixed cryoglobulinaemia glomerulonephritis, and one with end-stage kidney disease. Blocking and elution studies carried out on specimens with essential mixed cryoglobulinaemia provided evidence that the RF deposits derive from circulating monoclonal RF. This data suggests that RF participates in the formation of glomerular immune deposits in several forms of immune complex mediated glomerulonephritis.

Biopsy↗
PubMed1983

Suppression of post-apheresis autoantibody rebound in cryoglobulinemia and cold agglutinin hemolytic anemia.

We studied the effect of immunosuppressive treatment on the autoantibody rebound that follows autoantibody withdrawal accomplished by extracorporeal plasma treatment. The study was carried out on 9 patients, 8 having essential mixed cryoglobulinemia and 1 cold agglutinin hemolytic anemia. As immunosuppressive drugs we used either cyclophosphamide and prednisolone or arabinoside C and cyclophosphamide. The effect of immunosuppressive treatment on autoantibody rebound (Igm anti-IgG; IgM cold agglutinins) varied widely, a suppressive effect of varying degree having been observed in about half the cases treated with either drug regimen.

Anemia, Hemolytic, Autoimmune↗
PubMed1983

Blood temperature and cardiovascular stability in hemofiltration.

Temperature (T) changes in the blood flowing through the extracorporeal circuit markedly affect cardiovascular tolerance to fluid removal during either hemodialysis (HD) and isolated ultrafiltration. In this study we investigated the effect of blood T changes during postdilutional hemofiltration (HF). To this purpose we compared the changes in mean arterial pressure (MAP) and heart rate (HR) during HF and HD carried out at equivalent T of blood in the venous segment of the extracorporeal circuit. Results show that HF entails some heat loss from blood flowing in the extracorporeal circuit; if heat loss is made similar, HD affords nearly as much blood pressure protection as HF does. On the other hand at equivalent heat gain, HF causes nearly as much hypotension as HD does. We conclude that blood T changes in the extracorporeal circuit affect vascular stability (VS) even in HF. The marginal benefit of HF over HD, still observed at equalized T changes, remains to be elucidated.

Blood↗