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Biomedical subjects

A Valdivieso

Publications and source records attributed to A Valdivieso.

At least 19 recordsLinked to original sources
PubMed2003

Liver transplantation for hepatocellular carcinoma in cirrhotic patients.

A consecutive series of 88 patients underwent transplantation for hepatocellular carcinoma with cirrhosis over a 7-year period. Liver transplantation was indicated because of the tumor in 75 cases (85.2%); tumor was an incidental finding in 13 cases (14.8%). One patient was retransplanted due to primary nonfunction. The perioperative mortality was 4.5%. Tumor recurrence was observed in seven patients (7.95%) with incidental tumor recurrence in one case. As in patients with known primary liver tumors pretransplant, a thorough follow-up is advisable to establish an early diagnosis of recurrence. The actuarial survival for nonincidental hepatocellular carcinoma at 1, 3, and 5 year was 92%, 77%, and 75%, respectively. The differences in actuarial survival between hepatitis C negative and positive hepatocellular carcinoma were not significant (log-rank test P=.27), though there was a clear improvement in results (94%, 85%, and 78% vs 90%, 71%, and 71%), at 1, 3, and 5 years meaning that HCV infection is an important prognostic factor. Although transplantation for HCC has the advantages of removing the tumor and the cirrhotic liver, it remains a controversial topic. In our experience patients showing lesions less than 5 cm or three or fewer lesions experience an equivalent survival to transplanted patients who do not have cancer.

Adult↗
PubMed2003

Liver transplantation for hilar cholangiocarcinoma: Spanish experience.

INTRODUCTION: Palliative treatment for nondisseminated irresectable hilar cholangiocarcinoma (HCC) carries a 0% 5-year survival rate. The role of orthotopic liver transplantation (OLT) in these patients is controversial because the survival rate is lower than that for other indications for transplantation and the lack of available donor organs. The aim of this paper was to review the Spanish experience in OLT for HCC and identify prognostic factors for survival. METHODS: We retrospectively reviewed 36 patients undergoing OLT for HCC over 13 years. RESULTS: The actuarial survival rate at 1, 3, and 5 years was 82%, 53%, and 30%, respectively. The main cause of death was tumor recurrence (53%). In the univariate analysis, the factors for a poor prognosis were vascular invasion (P<.001) namely 0% survival at 3 years when present versus 63% and 35% at 3 and 5 years, respectively, when it was not; and stages III to IVA (P<.05), namely 15% survival at 5 years versus 47% for stages I to II. Lymph node and perineural invasion also reduce survival. In the multivariate analysis, the factors for poor prognosis included vascular invasion (P<.01) and stages III to IVA (P<.01). CONCLUSION: OLT for nondisseminated irresectable HCC has higher survival rates at 3 and 5 years than palliative treatments, especially with initial stage tumors, which means that more information is needed to better select cholangiocarcinoma patients for transplantation.

Bile Duct Neoplasms↗
PubMed2003

Liver transplantation for peripheral cholangiocarcinoma: Spanish experience.

INTRODUCTION: Palliative treatment for nondisseminated unresectable peripheral cholangiocarcinoma (PCC) carries a 0% 5-year survival rate. The role of orthotopic liver transplantation (OLT) in these patients is controversial because the survival rate is lower than with other indications for transplantation and the lack of available donor organs. The aim of this paper was to review the Spanish experience in OLT for PCC to identify prognostic factors for survival. METHODS: We retrospectively reviewed 23 patients undergoing OLT in Spain for PCC over a period of 13 years. RESULTS: The actuarial survival rates were 77%, 65%, and 42% at 1, 3, and 5 years, respectively. The main cause of death was tumor recurrence (35%). Prognotic factors for an adverse outcome were pTNM classification (P<.05) in the univariate analysis and perineural invasion (P<.05) and stages III or IVA (P<.05) in the multivariate analysis. CONCLUSIONS: OLT for nondisseminated irresectable PCC displays higher survival rates at 3 and 5 years than palliative treatments, especially for tumors in the initial stages, which means that more information is needed to help better select PCC patients for transplantation.

Bile Duct Neoplasms↗
PubMed2003

[Effect of PTH, phosphate, and metabolic acidosis on the progression of renal insufficiency in the azotemic rat].

In a previous study we have observed that NH4Cl-induced metabolic acidosis halted the progression of renal disease in azotemic rats with a high phosphate diet. We hypothesized that NH4Cl-induced metabolic acidosis may exert its protective effect by decreasing renal calcium content independent of serum levels of PTH and phosphate loading. To test this hypothesis we studied azotemic rats with very low phosphate diet or parathyroidectomy. Rats with low phosphate diet and parathyroidectomized rats developed renal failure after 5/6 nephrectomy, and in both groups the acid loading significantly decreased the progression of renal disease. Calcium renal content increased in both groups, even in rats with low phosphate diet, and this effect was also significantly decreased after an acid loading. Rats with acid loading developed greater hypertrophy of renal tissue than rats without acid loading. We conclude that NH4Cl-induced metabolic acidosis halted the progression of renal disease by decreasing calcium precipitation on renal tissue. Parathyroidectomy did not prevent progression of renal disease nor calcium precipitation, and a low phosphate diet in azotemic rats did not prevent increased calcium content on remnant renal tissue.

Acidosis↗
PubMed2001

Failure of high doses of calcitriol and hypercalcaemia to induce apoptosis in hyperplastic parathyroid glands of azotaemic rats.

BACKGROUND: Whether calcitriol administration, which is used to treat secondary hyperparathyroidism in dialysis patients, induces regression of parathyroid-gland hyperplasia remains a subject of interest and debate. If regression of the parathyroid gland were to occur, the presumed mechanism would be apoptosis. However, information on whether high doses of calcitriol can induce apoptosis of parathyroid cells in hyperplastic parathyroid glands is lacking. Consequently, high doses of calcitriol were given to azotaemic rats and the parathyroid glands were evaluated for apoptosis. METHODS: Rats were either sham-operated (two groups) or underwent a two-stage 5/6 nephrectomy (three groups). For the first 4 weeks, all rats were given a high (1.2%) phosphorus (P) diet to stimulate parathyroid gland growth and then were changed to a normal (0.6%) P diet for 2 weeks. At week 7, three of the five groups were given high doses of calcitriol (500 pmol/100 g body weight) intraperitoneally every 24 h during 72 h before sacrifice. The five groups during week 7 were: (i) normal renal function (NRF)+0.6% P diet; (ii) NRF+0.6% P+calcitriol; (iii) renal failure (RF)+0.6% P; (iv) RF+1.2% P+calcitriol; and (v) RF+0.6% P+calcitriol. Parathyroid glands were removed at sacrifice and the TUNEL stain was performed to detect apoptosis. RESULTS: At sacrifice, the respective serum calcium values in calcitriol-treated groups (groups 2, 4, and 5) were 15.52+/-0.26, 13.41+/-0.39 and 15.12+/-0.32 mg/dl. In group 3, PTH was 178+/-42 pg/ml, but in calcitriol-treated groups, PTH values were suppressed, 8+/-1 (group 2), 12+/-2 (group 4), and 7+/-1 pg/ml (group 5). Despite, the severe hypercalcaemia and marked PTH suppression in calcitriol-treated groups, the percentage of apoptotic cells in the parathyroid glands was very low (range 0.08+/-0.04 to 0.25+/-0.20%) and not different among the five groups. CONCLUSIONS: We found no evidence in hyperplastic parathyroid glands that apoptosis could be induced in azotaemic rats by the combination of high doses of calcitriol and severe hypercalcaemia despite the marked reduction in PTH levels that was observed.

Animals↗
PubMed2001

Effect of calcitriol treatment and withdrawal on hyperparathyroidism in haemodialysis patients with hypocalcaemia.

BACKGROUND: Calcitriol is used to treat secondary hyperparathyroidism in dialysis patients. For similarly elevated parathyroid hormone (PTH) levels, the PTH response to calcitriol treatment is believed to be better in hypocalcaemic dialysis patients than in dialysis patients with higher serum calcium values. Furthermore, few studies have evaluated the rapidity of the rebound in serum PTH values after prolonged treatment with calcitriol. Our goal was to evaluate (i) the PTH response to calcitriol treatment in hypocalcaemic haemodialysis patients, (ii) the rapidity of rebound in PTH after calcitriol treatment was stopped, and (iii) whether the effect of calcitriol treatment on PTH levels could be separated from those produced by changes in serum calcium and phosphate values. METHODS: Eight haemodialysis patients (29+/-3 years) with hypocalcaemia and hyperparathyroidism were treated thrice weekly with 2 microg of intravenous calcitriol and were dialysed with a 3.5 mEq/l calcium dialysate. Parathyroid function (PTH-calcium curve) was determined before and after 30 weeks of calcitriol treatment and 15 weeks after calcitriol treatment was stopped. RESULTS: Pretreatment PTH and ionized calcium values were 907+/-127 pg/ml and 3.89+/-0.12 mg/dl (normal, 4.52+/-0.07 mg/dl). During calcitriol treatment, one patient did not respond, but basal (predialysis) PTH values in the other seven patients decreased from 846+/-129 to 72+/-12 pg/ml, P<0.001 and in all seven patients, the decrease exceeded 85%. During the 15 weeks after calcitriol treatment was stopped, a slow rebound in basal PTH values in the seven patients was observed, 72+/-12 to 375+/-44 pg/ml. Covariance analysis was used to evaluate the three tests of parathyroid function (0, 30, and 45 weeks), and showed that calcitriol treatment was associated with reductions in maximal PTH values while reductions in basal PTH were affected by ionized calcium and serum phosphate. The basal/maximal PTH ratio and the set point of calcium were associated with changes in ionized calcium. CONCLUSIONS: In haemodialysis patients with hypocalcaemia, (i) moderate to severe hyperparathyroidism responded well to treatment with calcitriol, (ii) reductions in maximal PTH were calcitriol dependent while reductions in basal PTH were affected by the ionized calcium and serum phosphate concentrations, (iii) changes in the basal/maximal PTH ratio and the set point of calcium were calcium dependent, and (iv) the delayed rebound in basal PTH levels after withdrawal of calcitriol treatment may have been due to the long duration of treatment and the marked PTH suppression during treatment.

Adult↗
PubMed2000

Reduced natriuresis after oral sodium load in cholestatic rats: role of compartment volumes and ANP.

The purpose of this study was to assess the participation of the atrial natriuretic peptide (ANP)-cGMP system in electrolyte and volume handling of cholestatic rats submitted to an acute oral sodium load. Cholestasis was induced by ligation and section of the common bile duct (n = 51). Control rats were sham operated (n = 56). Three weeks after surgery, 24-hr urinary volume, sodium, potassium, cGMP and creatinine excretion were measured. Three days later, animals received 10 mmol/kg NaCl (1 M) by gavage, and urinary excretion was measured for 6 hr. In parallel groups of rats, plasma volume, electrolytes and ANP concentration, extracellular fluid volume (ECFV), and renal medullary ANP-induced cGMP production were determined in basal conditions or 1 hr after oral sodium overload. As compared with controls, cholestatic rats had a larger ECFV and higher plasma ANP (67.2 +/- 5.2 vs 39.7 +/- 3.5 pg/ml), but lower hematocrit and blood volume, and were hyponatremic. Cholestatic rats showed higher basal excretion of sodium, potassium, and volume than controls, but equal urinary cGMP. After the NaCl overload, cholestatic rats showed a reduced sodium excretion but equal urinary cGMP. One hr after sodium overload, both groups showed hypernatremia, but whereas in control rats ECFV and ANP increased (50.7 +/- 4.1 pg/ml), in cholestatic rats ECFV was unchanged, and plasma volume and ANP were reduced (37.5 +/- 5.8 pg/ml). ANP-induced cGMP production in renal medulla was similar in cholestatic and control nonloaded rats (14.2 +/- 5.2 vs 13.4 +/- 2.6 fmol/min/mg). One hr after the load, medullary cGMP production rose significantly in both groups, without difference between them (20.6 +/- 3.1 vs 22.7 +/- 1. 7 fmol/min/mg). We conclude that the blunted excretion of an acute oral sodium load in cholestatic rats is associated with lower plasma ANP due to differences in body fluid distribution and cannot be explained by renal refractoriness to ANP.

Animals↗
PubMed1999

[Severe and recent hyponatremia and hypokalemia associated to the use of hydrochlorothiazide, enalapril and citalopram. Clinical case].

We report a 72 years old hypertensive female, treated with enalapril 10 mg/day and hydrochlorothiazide 25 mg/day during three years. She presented a depressive disorder and cytalopram was prescribed in a dose of 10 mg/day. Two weeks before admission, a serum electrolyte analysis disclosed normal results and the cytalopram dose was increased to 20 mg/day. The patient was admitted with a hyponatremic encephalopathy with a plasma sodium of 100 mEq/L and a plasma potassium of 2.0 mEq/L. Cytalopram, enalapril and hydrochlorothiazide were discontinued, hypertonic NaCl and KCl were administered. The patient had a favorable evolution with a remarkable improvement of her symptoms.

Aged↗
PubMed1998

The kidney in chronic liver disease: circulatory abnormalities, renal sodium handling and role of natriuretic peptides.

Patients with chronic liver disease (Läennec's cirrhosis) present sodium chloride retention, leading to fluid accumulation within the extracellular space (edema) and specially in the abdomen (ascites). This article reviews the pathogenesis of the hemodynamic abnormalities observed in these patients, particularly the hypothesis of "primary arterial vasodilation", with an increased nitric oxide production by endothelial cells playing a major role in the pathogenesis of vasodilation. Since excessive renal sodium reabsorption precedes ascites formation, two hypotheses are analyzed with respect to the handling of renal sodium in chronic liver disease: the underfilling and overflow theories. Furthermore, the role of natriuretic peptides is reviewed, the increment in atrial natriuretic peptide observed in well compensated cirrhotic patients being considered as a compensatory response to volume expansion, although with renal resistance to this peptide in early stages of the disease. This review ends with an integrated explanation of the circulatory disturbances, renal sodium retention and renal resistance to atrial natriuretic peptide resulting in the sodium and water abnormalities observed in chronic liver disease.

Animals↗
PubMed1996

Pharmacokinetics and pharmacodynamics of penbutolol in healthy and cancer subjects: role of altered protein binding.

The pharmacokinetic and pharmacodynamic profiles of penbutolol were examined in healthy volunteers and in cancer patients using a pharmacokinetic/pharmacodynamic (pk/pd) model. After receiving a 40 mg single oral dose of penbutolol, the absorption rate constant, apparent volume of distribution and serum clearance of penbutolol were found to be reduced in the cancer group. Changes in the disposition of the conjugate metabolite were also observed in the cancer patients. Penbutolol unbound fraction in serum was statistically decreased (p < 0.005) in the cancer group, according to the increase in the serum levels of alpha 1-acid glycoprotein seen in that group (p < 0.05). The pharmacodynamic effect of penbutolol was measured as the reduction in heart rate (HR); in healthy volunteers, a linear relationship (p < 0.01) between effect and penbutolol serum concentrations (total or unbound) was found. In contrast, in cancer patients, values of HR did not vary statistically in respect to baseline values. These results show that in cancer patients, a change in the pharmacokinetics of penbutolol occurs (associated with changes in drug protein binding), together with an alteration in the pharmacodynamics.

Adult↗
PubMed1996

[Distal renal tubular acidosis and nephrolithiasis in 3 cases of primary Sjögren syndrome].

Tubulo interstitial nephritis, the main manifestation of renal involvement in Sjögren syndrome, may lead to a tubular dysfunction that is usually subclinical. We report three women, aged 32, 35 and 35 years old, with a primary Sjögren syndrome and symptomatic type I or distal tubular acidosis. Two patients had nephrolithiasis and one a nephrocalcinosis. Two had a basal hyperchloremic metabolic acidosis. The ammonium chloride acidification test was abnormal in all, demonstrating a distal tubular defect. None had proximal tubular dysfunction. All had an urinary pH over 6.5 and hypocitraturia and none had hypercalciuria. Renal calculi were composed of calcium oxalate and calcium phosphate in two patients and calcium phosphate and ammonium phosphate in the other. All women had positive antinuclear antibodies with mottled pattern, two had anti Ro antibodies and positive rheumatoid factor and one had hypergammaglobulinemia. None had anti La antibodies, crioglobulinemia or monoclonal proteins.

Acidosis, Renal Tubular↗
PubMed1995

Influence of vitamin C on the absorption and first pass metabolism of propranolol.

The effect of ascorbic acid on the availability of propranolol has been examined. After oral administration of propranolol 80 mg with or without ascorbic acid pretreatment (2 g), the plasma concentrations and urinary excretion of propranolol and its metabolites, 4-hydroxy-propranolol and propranolol-conjugated, were determined by HPLC. Compared to controls, vitamin C decreased the maximum concentration of propranolol from 463 to 334 nmol.l-1, and the area under the propranolol concentration-time curve (from 0 to 24 hours) from 3.13 to 1.96 mumol.l-1.h. The time to reach maximum propranolol concentration was increased from 1.9 to 2.7. The total amount of drug recovered in urine has also significantly diminished (from 12.6 to 4.29 mg). No change in elimination rate was observed, indicating that ascorbic acid had affected both the absorption process and the first pass metabolism. The heart-rate decreased less when propranolol was administered with ascorbic acid in comparison to control subjects, although this interaction has little biological importance.

Administration, Oral↗
PubMed1995

Is it worth using mechanical sutures in gastric surgery?

The use of stapler devices in gastrointestinal surgery has to be justified by the results. Since the cost of staplers is very high, their use should be followed by some advantage in the operating time, the morbidity or mortality rate or the postoperative stay. We have found a slight shortening in the operating time, but only statistically significant for Billroth I, and in the postoperative stay only for oesophagojejunostomies mechanically performed. We have not found any advantage with the other techniques and in the other parameters. Consequently, the use of staplers in gastric surgery should be carefully assessed by the surgeon for each patient in particular, and only used in those cases where a real benefit will be presumed.

Adult↗
PubMed1993

Propranolol absorption in peptic ulcer disease.

This study was designed to determine whether gastroduodenal ulcer influences propranolol absorption. Eleven patients with peptic ulcer disease and eight healthy subjects received 80 mg of propranolol orally. Serum propranolol levels were measured with high-performance liquid chromatography. Ulcer patients showed a significant decrease in mean peak concentration of propranolol (90 +/- 12 ng/ml versus 151 +/- 23 ng/ml) (p < 0.025), in the absorption constant (1.43 +/- 0.21 h-1 versus 0.96 +/- 0.12 h-1) (p < 0.05), and in the area under concentration-time curve (802 +/- 129 ng/ml.h versus 492 +/- 73 ng/ml.h) (p < 0.05). No significant difference was seen in drug effect on the heart at 90 min. We conclude that propranolol is absorbed more slowly in ulcer patients than in healthy subjects, but this delay has no clinical effect after a single dose.

Adult↗
PubMed1993

Renal vascular and excretory resistance to atrial natriuretic peptide in pre-cirrhotic, bile-duct ligated rats.

Renal response to atrial natriuretic peptide in chronic cholestasis was studied in anaesthetized rats and in their isolated perfused kidneys. Cholestasis was induced by bile duct section after ligature, while controls were sham operated. Three weeks after surgery, cholestatic rats showed moderate arterial hypotension, elevated diuresis and no differences in urinary sodium, glomerular filtration rate (GFR) and fractional sodium excretion (FENa), when compared to controls. Isolated kidneys of cholestatic rats had equal basal diuresis and less natriuresis than the controls. Cholestatic rats presented blunted natriuretic and diuretic responses to iv injections of atrial natriuretic peptide (ANP 0.5 microgram), associated with reduced increments in GFR and FENa, when compared with controls. Similarly, the diuretic-natriuretic response of isolated kidneys to ANP (3.5 x 10(-9) M) was greatly attenuated in this group. ANP did not increase perfusion pressure in cholestatic rats, as it did in controls. These results indicate that animals with chronic cholestasis present refractoriness to ANP, which might be mediated by a direct impairment at the renal vascular and tubular sites for ANP action.

Analysis of Variance↗