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Biomedical subjects

R Correa-Rotter

Publications and source records attributed to R Correa-Rotter.

At least 19 recordsLinked to original sources
PubMed2001

Two-year effects of alendronate on bone mineral density and vertebral fracture in patients receiving glucocorticoids: a randomized, double-blind, placebo-controlled extension trial.

OBJECTIVE: To evaluate the continued efficacy and safety of alendronate (ALN) for up to 2 years in patients receiving glucocorticoids. METHODS: This is a 12-month extension of a previously completed 1-year trial of daily ALN, performed to evaluate the effects of ALN over a total of 2 years in 66 men and 142 women continuing to receive at least 7.5 mg of prednisone or equivalent daily. All patients received supplemental calcium and vitamin D. The primary end point was the mean percentage change in lumbar spine bone mineral density (BMD) from baseline to 24 months. Other outcomes included changes in hip and total body BMD, biochemical markers of bone turnover, radiographic joint damage of the hands, and vertebral fracture incidence. RESULTS: The mean (+/-SEM) lumbar spine BMD increased by 2.8 +/- 0.6%, 3.9 +/- 0.7%, and 3.7 +/- 0.6%, respectively, in the groups that received 5 mg, 10 mg, and 2.5/10 mg of ALN daily (P < or = 0.001) and decreased by -0.8 +/- 0.6% in the placebo group (P not significant) over 24 months. In patients receiving any dose of ALN, BMD was increased at the trochanter (P < or = 0.05) and maintained at the femoral neck. Total body BMD was increased in patients receiving 5 or 10 mg ALN (P < or = 0.01). These 2 dose levels of ALN were more effective than placebo at all sites (P < or = 0.05). Bone turnover markers (N-telopeptides of type I collagen and bone-specific alkaline phosphatase) decreased 60% and 25%, respectively, during treatment with ALN (P < or = 0.05). There were fewer patients with new vertebral fractures in the ALN group versus the placebo group (0.7% versus 6.8%; P = 0.026). The safety profile was similar between treatment groups. CONCLUSION: Alendronate is an effective, well-tolerated therapy for the prevention and treatment of glucocorticoid-induced osteoporosis, with sustained treatment advantages for up to 2 years.

Adult↗
PubMed2001

The cost barrier to renal replacement therapy and peritoneal dialysis in the developing world.

The socioeconomic statuses of developing nations are diverse. Government policies for reimbursement or coverage of treatment for end-stage renal failure vary greatly from one country to another. Clearly, treatment rates correlate with the gross domestic product and the decision-making process for choosing a specific renal replacement modality is highly influenced by non medical factors. Particularly, those non medical factors include cost issues and the availability of medical and technical resources. Developing nations are experiencing an "epidemiologic transition" as birth rates drop and their populations age. That change in population demographics will undoubtedly increase even further the number of patients at risk of developing end-stage renal disease. Those nations will need to summon the commitment to devote a higher percentage of their resources to treating end-stage renal disease. Finally, when a modality is clearly better for a particular patient, medical indications should play a larger role in the final decision. That approach may prove to be highly useful not only in terms of cost effectiveness and long-term results for the health system, but also in terms of a better quality of life for the patient.

Costs and Cost Analysis↗
PubMed2001

The problem of the high transporter: is survival decreased?

The mechanisms responsible for the problem status of high transporters are diverse. High transporters have increased protein losses that may play a role in the presence of hypoalbuminemia and malnutrition. On the other hand, high transport induces increased glucose absorption, which may in turn be responsible for anorexia and increased atherogenesis--issues not discussed here, but clearly of major importance. And finally, the impaired ultrafiltration present in the high transporter leads to fluid overload, which is one of the driving forces for ventricular hypertrophy, hypertension, and increased cardiovascular risk--cardiovascular events being most prevalent cause of death in dialysis patients. All of the factors previously discussed--and others--may preclude some high transporters from being good candidates for peritoneal dialysis. Yet many others may still do well if the prescription is individually tailored to the particular patient.

Biological Transport↗
PubMed2000

Serum erythropoietin levels in kidney donors after renal transplantation.

BACKGROUND: Renal transplantation is the treatment of choice for many patients with end-stage renal disease. In the donor, renal excretory function is not affected after nephrectomy; however, little is known about other functions such as erythropoietin production. We studied the erythropoietin production in renal donors after nephrectomy. METHODS: We included healthy individuals fulfilling the criteria for kidney donation. Blood samples were collected before and monthly from 1 to 6 months after nephrectomy. Complete blood cell counts and erythropoietin were assayed. RESULTS: Eight kidney donors were studied. A significant increase in erythropoietin levels was observed during the first 3 months, but no difference was observed by the 4th month as compared with basal values. CONCLUSIONS: Erythropoietin production rose during the first 3 months after nephrectomy. However, erythropoietin was normal by the 4th month. Unchanged hemoglobin levels may suggest that the compensatory production of erythropoietin could participate in the preservation of an adequate physiological status of the donor after nephrectomy.

Adult↗
PubMed2000

Is high peritoneal transport rate an independent risk factor for CAPD mortality?

UNLABELLED: Is high peritoneal transport rate an independent risk factor for CAPD mortality? BACKGROUND: Patients with high peritoneal transport display the lowest serum albumin (SAlb) and the highest peritoneal protein loss. An association between high peritoneal membrane permeability and diabetes mellitus (DM) has been suggested. As malnutrition, hypoalbuminemia, and DM cause high mortality, it is probable that a high peritoneal transport rate is associated with high mortality on continuous ambulatory peritoneal dialysis (CAPD). The aim of the study was to identify whether a high peritoneal transport rate is an independent risk factor for mortality on CAPD. METHODS: We included 167 patients with a peritoneal equilibration test that was performed between January 1994 and July 1997. The endpoint was the patient's status (alive, dead, or lost) in December 1997. Survival analysis was done by the Kaplan-Meier method and multivariate Cox proportional-hazard model. RESULTS: DM was significantly more frequent in the high (H) peritoneal transport type (20 out of 33) and was less frequent in the low (L) transport group (3 out of 18). SAlb (g/dL) was significantly lower as the peritoneal transport type was higher [H 2.7 +/- 0.5, high average (HA) 2.9 +/- 0.7, low average (LA) 3.2 +/- 0.6, and L 3.6 +/- 0.5]. Serum creatinine (SCr) was significantly higher in the L transport type (12.0 +/- 4.3 mg/dL) than in the other transport groups (H 8.7 +/- 3.1, HA 8.6 +/- 3.7, and LA 9.6 +/- 4.5). No other differences were found between peritoneal transport types. In the univariate analysis, high peritoneal transport rate, DM, low SCr, low SAlb, and older age significantly predicted mortality. However, in the multivariate analysis (chi2 = 40.55, P < 0.0001), only DM (b = 1.34, P = 0.0001), low SCr (b = -0.11, P = 0.02), and high peritoneal transport rate (b = 2.6, P = 0.06) were shown as mortality risk factors. CONCLUSIONS: DM was the most important risk factor for mortality on CAPD. A high peritoneal transport rate also predicted mortality, yet its role seems to be related to the presence of DM. The role of higher SCr predicting a better survival might have been associated with a better nutritional status. Hypoalbuminemia, previously shown as risk factor for mortality, did not play an important role in this study, probably because of its collinearity with DM.

Adult↗
PubMed1998

Prevention of peritonitis with disconnect systems in CAPD: a randomized controlled trial. The Mexican Nephrology Collaborative Study Group.

BACKGROUND: Recently, disconnect systems for CAPD that are associated with a reduced frequency of peritonitis have been introduced. Our objective was to compare the incidence of peritonitis using three current CAPD systems in a high-risk population with low educational and socioeconomic levels, and high prevalence of malnutrition. METHODS: In a prospective controlled trial, 147 patients commencing CAPD were randomly assigned to one of three groups: 29 to the conventional, 57 to the Y-set, and 61 to the twin bag systems. The number of peritonitis episodes was registered, and patients were followed up for an average of 11.3 months. RESULTS: The average peritonitis-free interval for the conventional group was 6.1 months, for the Y system was 12.0 months, and for the twin bag was 24.8 months (P < 0.001). By multivariate analysis, the only factor associated with peritonitis was the CAPD system. Peritonitis-related hospitalization was 5.3 +/- 2.0, 2.7 +/- 1.0, and 1.5 +/- 0.9 days/patient/year in the conventional, Y system, and twin bag groups, respectively. The cost per bag was similar for the conventional and Y system, but higher for the twin bag. However, the total costs of treatment (pesos/patient/year) were lower for twin bag (62,159 for the conventional, 70,275 for the Y system, and 54,387 for the twin bag), due to the lower peritonitis incidence and associated hospitalizations. CONCLUSIONS: Y system and twin bag use was associated with a reduction of 50 and 75% peritonitis incidence, respectively, in patients on CAPD. The cost of the twin bag was actually lower, because of savings from a decreased usage of antibiotics and fewer hospitalizations.

Adult↗
PubMed1998

Prospective biochemical and scintigraphic evaluation of autografted normal parathyroid glands in patients undergoing thyroid operations.

BACKGROUND: Parathyroid autotransplantation has been widely used in thyroid operations. Few studies have assessed the function of the autotransplanted glands. The aim of this study was to evaluate the success rate, pattern of biochemical function, and scintigraphic appearance of parathyroid autografts in patients undergoing thyroid operations. METHODS: Twelve patients in whom 1 parathyroid gland was removed during thyroid operation were included. Glands were fragmented and autografted into individual pockets in the brachioradialis muscle of the nondominant forearm. Parathyroid hormone levels were measured in both arms the day of autotransplantation and 2 weeks and 1, 2, 3, and 6 months after operation. Serum calcium levels were also measured at each interval. Sestamibi scanning was performed 6 months after operation in 7 patients. RESULTS: All patients were women with a mean age of 50 +/- 15 years. Serum calcium levels were normal during follow-up. A gradient of parathyroid hormone level of 1.5 or greater between the autotransplanted and nontransplanted arm was found in 10 patients. Isotope uptake at the site of the parathyroid autotransplant was demonstrated in the 7 patients evaluated. CONCLUSIONS: Biochemical function of autotransplanted normal parathyroid tissue was documented in 83% of the patients. Sestamibi scintiscans were able to identify the autotransplanted tissue.

Adult↗
PubMed1998

Electroneutral Na-coupled cotransporter expression in the kidney during variations of NaCl and water metabolism.

The purpose of the present study was to analyze the long-term regulation of renal bumetanide-sensitive Na+-K+-2Cl- cotransporter and thiazide-sensitive Na+-Cl- cotransporter gene expression during changes in NaCl and water metabolism. Male Wistar rats exposed to high or low NaCl intake, saline loading, dehydration, water loading, and furosemide administration during 7 days were studied. Control groups had access to regular food and tap water. Rats were kept in metabolic cages for 4 days before and during the experiment to determine daily urinary electrolyte excretion and osmolarity. At the end of the experiment, creatinine clearance and serum electrolyte levels were also measured. Kidneys were excised and macroscopically subdivided into cortex and outer and inner medulla. Total RNA was extracted from each individual cortex or outer medulla by use of the guanidine/cesium chloride method. The Na+-K+-2Cl- cotransporter expression in outer medulla total RNA was assessed by nonradioactive Northern blot analysis and the Na+-Cl- cotransporter expression in renal cortex total RNA was assessed by semiquantitative polymerase chain reaction. Experimental maneuvers were adequately tolerated, and all groups developed the appropriate renal response to each challenge. However, the level of expression of both cotransporters did not change in any model, except for a 2.8-fold increase in the Na+-Cl- cotransporter expression during dehydration. We conclude that nephron adaptation to 7-day modifications in NaCl and water metabolism does not include changes in the amount of electroneutral sodium-coupled cotransporter gene expression at the mRNA level.

Animals↗
PubMed1998

Induction of clusterin in tubules of nephrotic rats.

Clusterin is a glycoprotein induced after renal tubular cell injury. The purpose of this study was to examine the expression of clusterin in a disease model characterized early in its course by predominant glomerular injury. Male Wistar rats (weighing 251 +/- 16 g) were treated with puromycin aminonucleoside (PAN: 15 mg/100 g body wt, subcutaneously; n = 7) or vehicle (control; n = 8). The kidneys were harvested 6 d after treatment, when rats were nephrotic. Clusterin mRNA was markedly induced in the kidneys of nephrotic rats (8.5-fold versus control). Immunohistochemistry studies demonstrated clusterin primarily in tubules in the cortex and medulla. Many of the tubules staining for clusterin were dilated but had no other differentiating morphologic features. Increased numbers of proliferating tubular cells were seen at 6 d, but there was no correlation between these cells and clusterin staining. In contrast to the extent and pattern of clusterin staining, vimentin was seen in only sporadic, dilated tubules, in addition to its expected glomerular localization. An increase in clusterin mRNA was not seen 1, 2, or 4 d after PAN injection. In conclusion, tubular epithelial cell induction of clusterin occurs in the kidneys of nephrotic rats. The appearance of clusterin precedes the development of tubulointerstitial disease and may be a response to the proteinuria.

Animals↗
PubMed1997

Peritoneal transport kinetics correlate with serum albumin but not with the overall nutritional status in CAPD patients.

The present study evaluates the influence of the peritoneal transport rate (PTR) on the nutritional status of continuous ambulatory peritoneal dialysis (CAPD) patients. Additionally, protein intake, dialysis adequacy, and other clinical variables were analyzed. Forty-two CAPD patients were concurrently subjected to the peritoneal equilibration test, a nutritional evaluation that included 24-hour dietary recall, and nutritional scoring system that included anthropometric, biochemical, and subjective parameters. Eight patients were high, 14 were high-average, 16 were low-average, and four were low transporters. Nine patients had normal nutritional status; six had mild, nine had moderate, and 18 had severe malnutrition. Malnutrition was inversely correlated (P < 0.05) with body surface, hemoglobin, and residual renal function, but not with PTR (r = 0.14; P = 0.38). In the multivariate analysis, the nutritional status was not predicted by the PTR, protein intake, or dialysis adequacy variables. When serum albumin (SA) level was evaluated as an isolated nutritional indicator, the most significant predictors were dialysate to plasma creatinine ratio at 4 hours (D/P4), body surface area, age, and diabetes mellitus. High transporters receiving a high dose of dialysis displayed a trend of having lower SA levels, whereas low-average transporters receiving a high dose of dialysis showed a trend of have higher SA levels. In conclusion, there was no correlation between PTR and nutritional status. In the multivariate analysis, no association was found between nutritional status and PTR, dialysis adequacy, and protein intake. The best predictors for SA are PTR, body surface area, age, and diabetes mellitus.

Analysis of Variance↗
PubMed1997

Renin, prorenin, and renin gene expression in rats with acute nephrotic syndrome.

1. The concentration of total, active and inactive renin was analysed in plasma, urine and kidney from control (C), pair-fed (PF) and nephrotic (NS) rats, as well as renin mRNA levels in kidney, liver and brain. 2. Nephrotic syndrome were induced by a single subcutaneous injection of puromycin aminonucleoside (PAN) and determinations were made 6 days after PAN injection. 3. Plasma total renin did not change, active renin increased in NS rats with respect to PF and C groups and in PF rats with respect to C. In contrast, the inactive renin percentage decreased in NS rats with respect to PF and C groups and in PF animals with respect to C. Total, active and inactive renal renin content did not change and active and inactive renin were significantly excreted by urine with no changes in the prorenin percentage with respect to C and PF groups. 4. In both NS and PF groups, renin mRNA levels did not change in any of the tissues studied. In another group of rats, kidney renin mRNA levels were measured on days 1, 3, 5 and 7 after PAN injection and no time-course changes in its expression were found. 5. These results suggest that renin gene expression is not altered in acute nephrotic syndrome and that plasma renin concentration is regulated at the translational or post-translational level in this experimental model.

Acute Disease↗
PubMed1997

Hepatic and extrahepatic angiotensinogen gene expression in rats with acute nephrotic syndrome.

Plasma concentration and urine excretion of the renin-angiotensin system proteins are altered in rats with nephrotic syndrome (NS). In this work the messenger ribonucleic acid (mRNA) levels of angiotensinogen (Ao) were analyzed with the slot-blot hybridization technique in liver and other extrahepatic tissues: kidney, heart, brain, and adrenal gland from control, nephrotic, and pair-fed (PF) rats. NS was induced by a single injection of puromycin amino-nucleoside (PAN). Although a great urinary excretion and half-normal plasma levels of Ao were observed on day 6 after PAN injection, when NS was clearly established, hepatic Ao mRNA levels did not change. Furthermore, the Ao mRNA levels did not change in any of the extrahepatic tissues studied on day 6, nor did its hepatic levels at days 1, 3, 5, or 7 after PAN injection. These data suggest that the hepatic and extrahepatic Ao mRNA levels are unaltered during the development of the acute NS induced by PAN.

Acute Disease↗
PubMed1997

Regulation of hepatic angiotensinogen gene expression in nephrotic rats.

Plasma angiotensinogen (Ao) concentration (PAC), urinary Ao excretion (UAE), hepatic levels of Ao mRNA and plasma renin concentration (PRC) were studied in control and nephrotic rats subjected to the following treatments: dexamethasone (DEX), ethinyl-estradiol (EE), tri-iodothyronine (T3), bilateral nephrectomy (NX), captopril (CAP) and adrenalectomy (ADX). In nephrotic rats PAC diminished, UAE and PRC augmented and Ao mRNA levels were not altered. In control rats, DEX, EE, T3 and NX increased PAC and Ao mRNA levels whereas CAP diminished PAC but not affected Ao mRNA. ADX diminished PAC and Ao mRNA levels. In nephrotic rats, these treatments produced the same effect than in control rats except in ADX which did not affect PAC. These data suggest that the decreased PAC is not related to alterations in hepatic Ao gene expression but to elevated PRC and UAE.

Adrenalectomy↗
PubMed1996

Oral alendronate induces progressive increases in bone mass of the spine, hip, and total body over 3 years in postmenopausal women with osteoporosis.

To determine the effects of long-term daily oral alendronate sodium (ALN) on bone mass in postmenopausal women with osteoporosis, 19 centers enrolled 516 postmenopausal women aged 45-80 years with spine bone mineral density (BMD) at least 2.5 SD below the mean for young premenopausal women in a 3-year, double-blind, placebo-controlled study. Subjects were randomly allocated to one of four treatment groups: placebo; alendronate, 5 or 10 mg/day for 3 years; or alendronate, 20 mg/day for 2 years followed by 5 mg/day for the 3rd year. All patients received 500 mg/day of supplemental calcium to ensure adequate calcium intake. BMD was measured by dual-energy X-ray absorptiometry at several skeletal sites. Nonsignificant mean decreases in BMD of the spine, femoral neck, and trochanter of 0.6, 0.7, and 0.4%, respectively, occurred in the placebo group at 3 years. Relative to placebo-treated patients, spine BMD increased by 5.4%, 7.4%, and 8.4% in the 5, 10, and 20/5 mg ALN groups, respectively. Increases at the femoral neck were 3.5%, 5.5%, and 4.3%, and those at the trochanter were 5.1%, 7.2%, and 7.2%, respectively. Thus, efficacy of 10 and 20/5 mg ALN was similar, whereas the 5 mg dose was less effective. BMD continued to increase over the entire 3-year study duration in the ALN-treated groups and, compared with the other dosage groups, 10 mg ALN produced the largest gains in BMD during the 3rd year. Changes in biochemical markers of bone turnover and mineral homeostasis confirmed the effect of ALN to decrease bone turnover to a new steady-state level. The safety and tolerability of ALN were comparable with those of placebo. In summary, 10 mg daily oral ALN given for 3 years significantly and progressively increases bone mass and is a generally well-tolerated treatment for osteoporosis in postmenopausal women.

Administration, Oral↗
PubMed1996

Prevalence of malnutrition in Mexican CAPD diabetic and nondiabetic patients.

Malnutrition is often present on continuous ambulatory peritoneal dialysis (CAPD), and contributes to morbidity and mortality. Diabetics (DM) have an increased risk for developing malnutrition. Our purpose was to assess the nutritional status (NS) of our CAPD population, to define NS differences between DM and nondiabetics (NoDM), and to identify NS-related factors. Patients were subjected to a nutritional assessment, which included a 24-hour dietary recall and a nutritional scoring system including anthropometric, biochemical, and subjective evaluation, and that classifies patients as: normal, and mildly, moderately, and severely malnourished. We studied 90 patients: 35 DM and 55 NoDM. In our whole population we observed a high frequency of malnutrition: NS was normal in 18%, and 20% had mild, 24% had moderate, and 38% had severe malnutrition. Ninety-one percent of DM and 76% of NoDM showed some degree of malnutrition. DM patients had significantly higher levels of malnutrition (p = 0.02), were significantly older, had more body fat, and spent less time on dialysis. There were 37 males and 53 females. Sex distribution was similar between DM and NoDM. Seventy-six percent of males and 86% of females had malnutrition. Moderate and severe malnourishment were more frequent in females. DM and female sex were the strongest predictors for moderate and severe malnutrition.

Adult↗