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Biomedical subjects

A Cases

Publications and source records attributed to A Cases.

At least 37 records · Page 2Linked to original sources
PubMed1993

Minimal-change glomerulopathy and carcinoma. Report of two cases and review of the literature.

We describe 2 patients with minimal-change glomerulopathy (MCG) associated with an undifferentiated carcinoma of unknown origin and urothelial carcinoma. Oliguric acute renal failure and histopathological changes consistent with acute tubular necrosis were also observed. Fourteen other cases of MCG complicating solid tumors reported in the literature are reviewed. MCG should be included in the nephropathies which cause nephrotic syndrome in adult patients with carcinoma.

Acute Kidney Injury↗
PubMed1993

Platelet activation on hemodialysis: influence of dialysis membranes.

During hemodialysis, platelets are activated and release alpha-granule-specific proteins. GMP-140 is a glycoprotein stored in the alpha-granules of platelets, which is selectively expressed on the plasma membrane of activated platelets. Using a specific monoclonal antibody against this protein (CD 62), we have evaluated the influence of different dialysis membranes on hemodialysis-induced platelet activation in vivo by flow cytometry in nine patients with end-stage renal disease on maintenance hemodialysis. Five membranes were evaluated: Cuprophane, cellulose acetate, polymethylmethacrylate, polysulphone and polyacrylonitrile (AN-69). Blood samples were obtained before hemodialysis and from the inlet and outlet lines five minutes after the beginning of hemodialysis. A significant increase in the GMP-140 expression was observed in samples obtained from the outlet line compared with samples obtained from the inlet line for all membranes evaluated, but the extent of this increase depended on the type of membrane used: Cuprophane 13.95 +/- 3.94%, cellulose acetate 7.4 +/- 4.52%, polymethylmethacrylate 6.93 +/- 4.6%, polysulphone 3.83 +/- 2%, and AN-69 2.14 +/- 2.19% (mean +/- SD). Cuprophane induced the highest degree of platelet activation (P < 0.05). Cellulose acetate and polymethylmethacrylate induced more platelet activation than polysulphone or AN-69 (P < 0.05). These data demonstrate that all hemodialysis membranes induce platelet activation but to a variable extent, cuprophane being the most activating membrane, cellulose acetate and polymethylmethacrylate showing an intermediate potential of activation, while the more biocompatible membranes, polysulphone and AN-69, inducing the lowest degree of platelet activation.

Adult↗
PubMed1993

Abnormal cytoskeletal assembly in platelets from uremic patients.

The mechanisms involved in the hemostatic abnormality of uremic patients remain obscure. We have explored the response of normal and uremic platelets to surface activation at the ultrastructural level and analyzed changes in the composition of proteins associated with normal and uremic platelet cytoskeletons after stimulation with thrombin (0.01 and 0.1 U/ml). Cytoskeletons were obtained by extraction with Triton X-100, processed by sodium dodecylsulfate-polyacrylamide gel electrophoresis, and the presence of cytoskeletal proteins analyzed by densitometry. Under static conditions, uremic platelets spread with difficulty on formvar-coated grids. The percentage of platelets that spread fully on this polymer surface was statistically reduced compared with that of control platelets (11 +/- 1.4 vs. 21 +/- 1.6; P < 0.05). An impairment of cytoskeletal organization was observed in resting uremic platelets but abnormalities were more evident after thrombin activation. The incorporation of actin into the cytoskeletons of thrombin-stimulated uremic platelets was significantly reduced with respect to controls (6 +/- 3% vs. 29 +/- 5%; P < 0.01 after 0.01 U/ml and 28 +/- 9% vs. 59 +/- 10%; P < 0.05 after 0.1 U/ml). Decreased associations of actin-binding protein (P < 0.01), alpha-actinin (P < 0.05), and tropomyosin (P < 0.05) with the cytoskeletons of uremic platelets were also noted. No difference was observed for the incorporation of myosin into the cytoskeletons of activated uremic platelets. These results suggest functional and biochemical alterations of the platelet cytoskeleton in uremia, which may contribute to the impairment of platelet function observed in uremic patients.

Adult↗
PubMed1992

Calciphylaxis in a hemodialysis patient: appearance after parathyroidectomy during a psoriatic flare.

Chronic renal failure patients are prone to soft tissue calcifications. A phenomenon of acute ischemic skin necrosis and dermohypodermic arteriolar medial calcification has been described recently in patients with chronic renal failure and secondary hyperparathyroidism (HPT). This phenomenon, termed calciphylaxis, occurs in response to certain factors, the most important of which appears to be an elevated blood calcium-phosphate product. Accordingly, parathyroidectomy in addition to normalization of calcium-phosphate product has been proposed as the only effective therapeutic approach for this condition. We describe a case of chronic renal failure with severe secondary HPT in which the patient developed calciphylaxis 4 days after the appearance of a psoriatic flare. Four months before, a subtotal parathyroidectomy was performed for severe HPT and at the time the ulcerations appeared, blood calcium-phosphate product was correct. Etiological and physiopathological aspects of calciphylaxis are discussed.

Calciphylaxis↗
PubMed1992

Recombinant human erythropoietin treatment improves platelet function in uremic patients.

The effect of recombinant human erythropoietin (rHuEPO) on primary hemostasis was tested in 19 hemodialyzed patients. Bleeding time, platelet aggregation and platelet interaction with vessel subendothelium (SE) under flow conditions were determined before treatment and after patients reached hematocrits greater than or equal to 30%. Two thrombotic events (an acute myocardial infarction and an AV fistula clotting) were recorded during the early stages of treatment. A shortening of average bleeding times (P less than 0.01), an increase in platelet count (P less than 0.01) and an improvement of platelet aggregation (P less than 0.01) and of platelet-SE interaction (P less than 0.01) were observed. A low correlation index was found between hematocrit and bleeding time (r = -0.351, P less than 0.05). To assess a possible effect of rHuEPO on platelet function, the same parameters were evaluated before and after receiving three doses of rHuEPO (40 U/kg i.v. post-hemodialysis) in 14 of the patients. No changes in platelet or erythrocyte counts were observed, the mean bleeding time remained unchanged, but platelet aggregation induced by arachidonic acid (P less than 0.05), ADP (P less than 0.01) and ristocetin (P less than 0.05) improved. Perfusion studies confirmed moderate but significant increases in the parameters that quantify platelet-SE interaction (P less than 0.05). Improvement of ADP-induced aggregation correlated with the increase of platelet adhesion to SE (r = 0.675, P less than 0.05). We conclude that rHuEPO treatment improves primary hemostasis in uremia through an increase of red cell mass but also through a beneficial effect on platelet function, which is independent of the hematocrit rise.

Adult↗
PubMed1992

Arginine vasopressin infusion increases plasma levels of atrial natriuretic factor in humans.

Seven normal subjects underwent sequential 20-min infusion of arginine vasopressin (AVP) at 0.5 and 2 ng/(kg.min) and a complete right-side heart hemodynamic evaluation during the study to analyze the effect of this hormone on atrial natriuretic factor (ANF) secretion in humans and to elucidate whether this effect was primary or secondary to the hemodynamic or hormonal changes induced by AVP. Plasma ANF levels increased at the end of the first (P less than 0.05) and second (P less than 0.01) infusion periods. No significant changes in mean arterial, pulmonary artery, right and left atrial pressures were recorded during the study. Cardiac output (P less than 0.05) and heart rate (P less than 0.05) decreased, while total vascular resistances (P less than 0.05) increased with respect to basal values in both infusion periods. Plasma renin activity decreased (P less than 0.01) at the end of the infusion, while plasma aldosterone, epinephrine and norepinephrine showed no significant changes. We conclude that arginine vasopressin increases plasma ANF levels in humans and that this effect cannot be ascribed to hemodynamic or hormonal changes induced by this hormone, suggesting a direct effect of vasopressin on the atrial myocyte.

Adult↗
PubMed1991

Tumor markers in chronic renal failure and hemodialysis patients.

Serum levels and the incidence of elevated levels of several tumor markers were measured in 30 patients with chronic renal failure (CRF) of different degrees, as well as in 36 hemodialyzed (HD) patients without clinical evidence of neoplasia. The tumor markers evaluated were carcinoembryonic antigen (CEA), CA 125, CA 15.3, CA 19.9, CA 50, alpha-fetoprotein, neuron-specific enolase (NSE), squamous cell carcinoma antigen (SCC), prostatic acid phosphatase and prostatic-specific antigen. Serum levels of CEA were above the cutoff limit in 33% of patients with CRF and 47% of HD patients, CA 50 was higher than normal values in 37 and 44% of patients, respectively. SCC was elevated in 43 and 72% of patients, respectively. Serum levels of CA 125 were elevated in 18% of patients with CRF and NSE in 36% of HD patients. In CRF several tumor markers (CEA, SCC, CA 50 and NSE) show a high false positive rate and may be unreliable for monitoring malignancies in uremic patients, while the other markers evaluated appear to maintain their specificity in this situation.

Adult↗
PubMed1991

[Late recurrence in pheochromocytoma: need for a long term follow up].

Pheochromocytoma is a catecholamine secreting tumor which has been traditionally considered as a potentially curable cause of hypertension. However, the existence of malignant pheochromocytomas as well as the problem which the recurrence of benign pheochromocytomas present, make the eradication of this tumor more complicated. It is note worthy the difficulty in localizing recurrent pheochromocytomas as well as the prognostic interest that presents the possibility of differentiating between recurrence and metastasis. We refer the case of a female patient suffering benign adrenal pheochromocytoma, who, 10 years it was surgically removed, presented a relapse of symptoms, and was diagnosed of extra-adrenal pheochromocytoma, in Zuckerkandl organ. The importance of performing a long term post-surgical follow-up in these patients is stressed.

Adrenal Gland Neoplasms↗
PubMed1990

[Effects of the treatment with human recombinant erythropoietin on primary hemostasis in uremic patients].

The effect of human recombinant erythropoietin (r-EPO) on primary hemostasia was studied in 9 patients undergoing hemodialysis. The analysis was performed before and after the hematocrit reached a value of 30%. The most important complications observed during the study period were a death for acute myocardial infarction in a patient with previous severe ischemic cardiopathy and a thrombosis of the venous line. The bleeding time shortened in four patients although the mean value did not change significantly. Platelet count showed a non significant increase. There was a significant improvement in in vitro platelet aggregability with ADP (p less than 0.05), arachidonic acid (p less than 0.05), adrenaline (p less than 0.05), and ristocetin (p less than 0.05) as well as in the parameters that quantify the interaction between platelets and subendothelium in in vitro experiments using perfused models (p less than 0.05). There were no significant changes in coagulation and fibrinolysis tests. The treatment with r-EPO improved primary hemostasia in uremic patients. This beneficial effect was due to the increased hematocrit and to the improvement of platelet function induced by r-EPO.

Adult↗
PubMed1990

Uremic platelets have a functional defect affecting the interaction of von Willebrand factor with glycoprotein IIb-IIIa.

Uremic patients have an impaired platelet function that has been related to membrane glycoprotein (GP) abnormalities. Using a perfusion system, we have studied the interaction of normal and uremic platelets with vessel subendothelium (SE) under flow conditions. Reconstituted blood containing washed platelets, purified von Willebrand factor (vWF) (1 U/mL), and normal washed red blood cells was exposed to de-endothelialized rabbit segments for 10 minutes at two different shear rates (800 and 1,600 seconds-1). In some experiments a monoclonal antibody to the GPIIb-IIIa complex (EDU3) was added to the perfusates. With normal platelets, the percentage of the vessel covered by platelets (%CS) was 23.1% +/- 3.7% at 800 seconds-1 and 30% +/- 4.3% at 1,600 seconds-1. Platelets were observed in contact or forming monolayers on vessel SE. EDU3 inhibited the spreading of normal platelets. The %CS (11.1% +/- 3.3%) was statistically decreased (P less than .01) and most of the platelets were observed in contact with the vessel surface. These data indicate that, under flow conditions, the interaction of vWF with GPIIb-IIIa can support the spreading of normal platelets in the absence of exogenous fibrinogen. Under the same experimental conditions, the interaction of uremic platelets with SE was markedly impaired at both shear rates studied (P less than .01 v normal platelets). The presence of EDU3 did not modify the interaction of uremic platelets. These results confirm the impairment of the platelet adhesion observed in uremic patients. Furthermore, they indicate the presence of a functional defect in the interaction of vWF with GPIIb-IIIa. The fact that perfusions with normal and uremic platelets in the presence of an antibody to the GPIIb-IIIa complex did not show any differences gives indirect evidence on a functionally normal interaction vWF/GPIb in uremic patients.

Blood Platelets↗
PubMed1990

[Lymphocyte beta 2-adrenergic receptors in pheochromocytoma].

To assess the effect of chronic exposure to high circulating catecholamine concentrations on the beta 2-adrenergic receptors, the density and affinity of lymphocyte beta 2-adrenergic receptors were measured in 5 patients with pheochromocytoma (2 males and 3 females, with a mean age of 39 +/- 12 years). In 4 patients the studies were repeated 15 days after tumor removal. Before surgery, all patients had high plasma catecholamine concentration. The density of beta 2-adrenergic receptors was reduced, although their affinity was within the reference range. There was an inverse correlation between plasma epinephrine concentration and beta 2-adrenergic receptor density (r = -0.959, p = 0.01). After surgical resection, plasma catecholamine concentrations and receptor density became normal. The dissociation constant decreased in the four patients. In conclusion, in the presence of chronically high levels of circulating catecholamines the density of lymphocyte beta 2-adrenergic receptors is reduced. However, it becomes normal when plasma catecholamine concentration returns to the reference values, the dynamic character of this regulation being thus shown. The measurement of these receptors in the lymphocyte could be useful for the diagnosis and follow up of patients with pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1990

Ocular and auditory toxicity in hemodialyzed patients receiving desferrioxamine.

During an 18-month period of study 41 hemodialyzed patients receiving desferrioxamine (10-40 mg/kg BW/3 times weekly) for the first time were monitored for detection of audiovisual toxicity. 6 patients presented clinical symptoms of visual or auditory toxicity. Moreover, detailed ophthalmologic and audiologic studies disclosed abnormalities in 7 more asymptomatic patients. Visual toxicity was of retinal origin and was characterized by a tritan-type dyschromatopsy, sometimes associated with a loss of visual acuity and pigmentary retinal deposits. Auditory toxicity was characterized by a mid- to high-frequency neurosensorial hearing loss and the lesion was of the cochlear type. Desferrioxamine withdrawal resulted in a complete recovery of visual function in 1 patient and partial recovery in 3, and a complete reversal of hearing loss in 3 patients and partial recovery in 3. This toxicity appeared in patients receiving the higher doses of desferrioxamine or coincided with the normalization of ferritin or aluminium serum levels. The data indicate that audiovisual toxicity is not an infrequent complication in hemodialyzed patients receiving desferrioxamine. Periodical audiovisual monitoring should be performed on hemodialyzed patients receiving the drug in order to detect adverse effects as early as possible.

Adult↗
PubMed1990

SCC antigen measured in malignant and nonmalignant diseases.

SCC antigen was measured in the serum of 214 patients with benign diseases and in 251 patients with various cancers. With 2.5 micrograms/L as the upper normal limit for serum, values were positive in 2.9% of 69 healthy subjects (I), 29.0% of 214 patients with benign pathologies (II), and 41% of 217 patients with active cancer (III). The highest values in group II were for patients in renal failure (64%) or with lung diseases (40%) or head-and-neck diseases (21.2%). Specificity of SCC increased (91.1%) when we excluded patients in renal failure or with creatinine values greater than 133 mumol/L. In group III, SCC values were abnormal in 57.7% of patients with squamous cell carcinoma, but in only 9.3% of those with other histological types (P less than 0.001). In squamous cell carcinoma of the lung, cervix, or head and neck, SCC values were related to tumor stage, values being highest in patients with metastases.

Adult↗
PubMed1989

[Prospective study of 75 episodes of sepsis in hemodialysed patients].

During a 38-month period the bacteremias developing in patients on hemodialysis from three centers of the Barcelona area were evaluated to assess their incidence, characteristics, and response to therapy. In the overall 13376 months of hemodialysis of the study, 75 episodes of bacteremia were detected in 64 patients; this amounts to an incidence of 5.6 episodes per 1000 hemodialysis months. The most common sources of becteremia were intravenous catheters (44%), which were mainly used as temporary vascular access, followed by the definitive vascular access (26%), the genitourinary system (10%), and the lung (6%). Twenty-seven episodes of bacteremia developed in 24 patients in whom dialysis had been started in the two previous months (11% of the overall number of new patients), and, in them, 77% originated in an intravenous catheter, while this was the origin of bacteremia in only 23% of the remaining patients. 72% of bacteremias were caused by gram positive organisms, particularly Staphylococcus aureus and Staphylococcus epidermidis (60%), followed, in frequency order, by aerobic gram negative bacilli (25%), particularly Escherichia coli and Pseudomonas. Stpahylococci were significantly associated with the vascular access, either if this was a catheter or not (81% of instances), while gram negative bacilli were associated with sources different from the vascular access (48% of instances). Severe complications included 2 cases of aortic valve endocarditis, one hemorrhagic shock caused by rupture of an infected vascular access, and one suppurative phlebitis associated with a hemodialysis catheter. Staphylococcal sepsis was randomly treated with vancomycin or vancomycin plus gentamicin, without differences in the results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Treatment of hyperkalaemia in renal failure: salbutamol v. insulin.

Three groups of patients with acute or chronic renal failure (GFR less than 5 ml/min) and hyperkalaemia (K+ greater than or equal to 6 mEq/l), similar in age, serum creatinine and pretreatment K+. Group A (n = 24) received salbutamol 0.5 mg i.v. in 15 min, group B (n = 10) received glucose 40 g i.v. plus 10 units insulin i.v. in 15 min, and group C (n = 10) received salbutamol 0.5 mg i.v., glucose 40 g i.v. and insulin 10 units i.v. over a 15-min period. Serum potassium was measured at 30, 60, 180 and 360 min after administration of treatment. All treatments reduced serum potassium, maximal at 30 or 60 min, and ranging from -0.5 +/- 0.1 to -1.5 +/- 0.2 mEq/l; patients in group C exhibited a significantly greater decrement in serum potassium, when compared to group B at 60 (-1.5 +/- 0.2 vs -1 +/- 0.1 mEq/l, respectively; P less than 0.01) and 180 min (-1.2 +/- 0.2 vs -0.7 +/- 0.1 mEq/l, respectively; P less than 0.05). There were no significant differences between groups A and C. Patients from group C had moderate tachycardia and more prolonged hyperglycaemia than those from group B, but all treatments were well tolerated.

Acute Kidney Injury↗
PubMed1989

Acute aluminum encephalopathy in an uremic patient.

A patient on maintenance hemodialysis developed an acute encephalopathy closely related to a rapid increase in serum aluminum levels. Aluminum hydroxide and sucralfate had been given in large amounts for the treatment of a gastrointestinal bleeding episode. The breach of the gastrointestinal barrier to aluminum absorption, the increase in gastric pH caused by cimetidine, and the presence of gastric telangiectasia acting together in a uremic patient could have precipitated the acute aluminum encephalopathy.

Acute Disease↗