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G Gamba

Publications and source records attributed to G Gamba.

At least 145 records · Page 8Linked to original sources
PubMedDate not supplied

Peritoneal protein loss in patients with high peritoneal permeability: comparison between continuous ambulatory peritoneal dialysis and daytime intermittent peritoneal dialysis.

BACKGROUND: Dialysate protein loss is involved in the etiology of hypoalbuminemia and malnutrition on continuous ambulatory peritoneal dialysis (CAPD). Patients with high peritoneal membrane permeability had the lowest serum albumin (Alb) and highest dialysate protein concentrations and achieved higher small solute dialysis/plasma equilibration in a shorter time than patients with low peritoneal transport. The aim of this prospective crossover study was to evaluate whether protein loss might be decreased in patients with high peritoneal permeability on short dwell-time (DT) peritoneal dialysis. METHODS: Five high and nine high-average peritoneal transport patients were subjected to the following sequential dialysis schemes (four exchanges/day, glucose 1.5%): scheme A, three daytime exchanges (4-6 h DT) and one nightly (8-12 h DT) for 2-3 days, scheme B, 3-h DT each and dry peritoneum at night during 5 days, a wash-out period similar to scheme A, and scheme C, 2-h DT each and dry peritoneum the remainder of day and night during 5 days. Dialysate Alb, IgG, IgA, and IgM losses and adequacy of dialysis were evaluated at the end of each scheme. RESULTS: Dialysate IgM was not detected. All protein losses were reduced with the short DT dialysis schemes; however, dialysis CCl and KT/V(urea) were also decreased. In patients with high peritoneal transport type, the 3-h DT dialysis scheme achieved a reduction in Alb loss without significant reduction of adequacy of dialysis. CONCLUSIONS: Peritoneal Alb, IgG, and IgA losses are significantly reduced in patients with high peritoneal permeability on short dwell-time dialysis and extended dry periods. However, a reduction of dialysis contribution to small solute clearances was also observed, Three-hour dwell-time dialysis may be particularly useful in patients with high peritoneal transport type, as it tends to reduce peritoneal protein loss without notably reducing adequacy of dialysis.

Adult↗
PubMedDate not supplied

Protein kinase C activation reduces the function of the Na(+):K(+):2Cl(-) cotransporter in Xenopus laevis oocytes.

BACKGROUND: The basolateral isoform of the Na(+):K(+):2Cl(-) cotransporter is expressed in several epithelial and non-epithelial cells, in which it is involved in ion secretion processes and in cell volume regulation. In humans, this cotransporter has been implicated in the development of primary hypertension. The major goal of the present study was to characterize the effect of protein kinase C activation on the function of the Na(+):K(+):2Cl(-) cotransporter isoform present in Xenopus laevis oocytes. METHODS: Oocytes were surgically harvested from adult female Xenopus laevis frogs, defolliculated by incubation in frog ringer containing collagenase B (2 mg/mL) under vigorous shaking, and by hand under the microscope. Only stage V-VI oocytes were used in the study. After overnight incubation in regular frog Ringer, oocytes were switched to a Cl(-)-free ringer for at least 12 h before beginning uptake experiments. The function of the Na(+):K(+):2Cl(-) cotransporter was determined by assessing tracer 22Na(+) uptake in the control group as well as under several experimental conditions, such as changes in extracellular osmolarity, absence of one of the cotransported ions, or the presence of drugs such as the specific cotransporter inhibitor bumetanide, phorbol esters (TPA, PDBu, or 4alphaPDD), and the PKC inhibitor bisindolylmaleimide I. At the end of the uptake period, tracer Na(+) uptake was counted by liquid scintillation of each individual oocyte previously dissolved in SDS. RESULTS: Xenopus oocytes exhibited a bumetanide-sensitive Na(+):K(+):2Cl(-) cotransporter in the plasma membrane activated by hypertonicity and inhibited by hypotonicity. The bumetanide-sensitive fraction of Na(+) uptake was significantly reduced by the addition of phorbol esters TPA or PDBu to the uptake media. This inhibitory effect of PKC activators was dose- and time-dependent. Phorbol ester 4alphaPDD, which cannot activate PKC, exhibited no effect on Na(+):K(+):2Cl(-) cotransporter function. In addition, pretreatment of oocytes with the PKC inhibitor bisindolylmaleimide I partially abolished TPA-induced reduction in the cotransporter function. CONCLUSION: In defolliculated Xenopus laevis oocytes, phorbol esters reduce the function of the Na(+):K(+):2Cl(-) cotransporter by a mechanism that includes the activation of an endogenous PKC.

Animals↗
PubMedDate not supplied

The many roles of the calcium-sensing receptor in health and disease.

The physiological relevance of calcium in many vital processes requires that its concentration in extracellular fluids be kept within a narrow range. The near-constancy of this parameter emphasizes the remarkable sensitivity of cells sensing changes in extracellular calcium concentration to minimal fluctuations (< 2%) and the level of sophistication of the homeostatic system (1). The identification of a cell surface, Ca2+ (polyvalent cation)-sensing receptor (CaR), has shed considerable light on the molecular aspects of hypercalcemia on cell function (2). Activation of the receptor by calcium triggers an intracellular cascade of second messengers producing a variety of biological effects, many of which have yet to be understood. This suggests, for the first time, that Ca2+ can exert its effects in a hormone-like fashion without crossing the plasma membrane. The demonstration that inherited genetic disorders of Ca2+ homeostasis are associated with mutations that reduce or enhance responsiveness of the receptor to extracellular Ca2+ concentration clearly proposes CaR as the main regulator of divalent mineral ion excretion (3). This hypothesis is confirmed by the assessment of the presence of the receptor in all regions involved in Ca2+ homeostasis (e.g., parathyroid glands, kidney, calcitonin-secreting C cells, bone-derived cell lines, and intestine) (1,4-8). Recently, the receptor has also been found in regions not normally involved in mineral ion metabolism, such as the brain, eye, stomach, and pancreas (9-13). This clearly indicates a much broader relevance of CaR in the maintenance of local ionic homeostasis and, possibly, in the involvement in vital processes such as the regulation of cell fate.

Animals↗
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Effects of dimethylformamide (DMF) on coagulation and platelet activity.

The effects of dimethylformamide (DMF) on hemostatic functions, especially on platelet activity, were examined both in vitro and in vivo in 15 workers exposed to DMF (27 mg/m3, median value). Twenty-eight control subjects who were not exposed to DMF, but comparable for age, anthropometric data, and smoking habits, were also studied. Workers exposed to DMF showed a decrease in the number of platelets and had longer coagulation times, probably due to a change caused by DMF on the membrane receptor of platelets and on the phospholipid components of the clotting system.

Adenosine Diphosphate↗
PubMedDate not supplied

[Continuous hemodialysis in the treatment of acute kidney failure].

INTRODUCTION: Continuous replacement therapy of renal function has gained acceptance over the last decade for the treatment of acute renal failure. In the present study we present our experience using continuous hemodialysis (CHD) in our institution. PATIENTS AND METHODS: This is a prospective analysis of the CHD treated patients in the intensive care unit (ICU) of our institution over an 24-month period. CHD was performed through a double-lumen catheter such as Mahurkar. We have performed 28 CHD procedures in 28 patients, from which four were excluded from the analysis. Three patients were excluded as CHD lasted less than 12 hours and one patient because he had chronic renal failure. The studied variables were: heart and respiratory rate, mean arterial pressure, body temperature, APACHE II classification status, arterial gasometry, cell blood count, BUN, creatinine, serum electrolytes, and hepatic enzymes. We also registered urine output, diuretic use, and the mean dose of inotropic drugs employed per day. These variables were obtained at the admittance to the ICU, before the initiation of CHD and after 24 and 48 hours. We also registered age, gender, and final evolution. RESULTS: We evaluated 24 patients with mean age of 58.1 +/- 17.5 years in which CHD was use for a mean time of 4.6 +/- 2.8 days. Total ultrafiltrate was 19.5 +/- 8.4 liters, for a mean of 4.2 liters per day. CHD resulted in improvement of heart and respiratory rate, mean arterial pressure and laboratory variables such as arterial pH, bicarbonate concentration, BUN and potassium. It also decreased significant by the use of inotropic drugs. Five out of twenty-four patients survived (20.8%). The survived patients had significant lower age than the died patients (39.2 +/- 20 years vs. 63 +/- 13.3; p < 0.001), lower time between the admittance to ICU and the beginning of CHD (1.4 +/- 0.5 days vs. 3.5 +/- 2.6; p < 0.01) and lower APACHE II classification at admittance to ICU (7.4 +/- 1.6 vs. 19.0 +/- 2.7; p < 0.001) and at the start of CHD (13.6 +/- 3.2 vs. 24.7 +/- 3.7; p < 0.001). However, multivariate analysis revealed that the only variable associated with a better survival was a lower time between the admittance to intensive care and the beginning of CHD. DISCUSSION: CHD is a safe technique that can be used for acute renal failure patients who have contraindications for intermittent HD. This technique can be used in hospitals offering intermittent hemodialysis and intensive care. CHD use is associated with improvement of hemodynamic and metabolic alterations in patients with shock. Our data support the concept that the earlier the initiation of CHD the better the prognosis.

APACHE↗
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[Percutaneous kidney biopsy, analysis of 26 years: complication rate and risk factors; comment].

UNLABELLED: Percutaneous renal biopsy is an invasive procedure that can result in major and minor complications. The objective of this study was to know the frequency and type of complications in relation with this procedure, as well as the efficacy to obtain enough material for diagnosis. METHODS: Retrospective study. We review the charts of patients to whom a percutaneous renal biopsy of native kidneys was done between January 1970 and March 1996. The following data were obtained: age, gender, clinical and histopathological diagnosis, complications associated with the procedure (minor: hematuria, local infections, hematoma; major: transfusions, severe infections, surgery, nephrectomy, arteriography, embolism and death). RESULTS: We analyzed 1,005 renal biopsies in 840 patients, mean age 37.7 +/- 13.1 years, 67% female. There were no complications in 88.8% (893 biopsies), minor complications in 8.65% (87 biopsies) and only in 2.4% of the procedures major complications. We divided the cases in two groups: percutaneous renal biopsy without complications (n = 893, 89%) and with complications (n = 112, 11%). The most frequent complications were hematuria (91 cases, 9.1%) and perirenal hematoma (29 cases, 2.7%). In these cases transfusion was required in 2.4% (26). Infectious complications were: urosepsis in 7 cases (0.7%), bacteremia, sepsis and perirenal abscesses (1 case each, 0.1%). One patient died because of multiple complications (0.1%). We observed greater risk of major complications on patients in those who biopsy was done because of acute renal failure (OR 4.03, p < 0.003). DISCUSSION: In our experience percutaneous renal biopsy is a low risk procedure. Most complications are minor and without clinical repercussion. There must be a strict selection criteria of the patients to whom percutaneous renal biopsy is going to be done because of the risk of severe complications.

Abscess↗
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[Hepatitis C viral in patients with terminal chronic kidney failure. I. Prevalence].

BACKGROUND: The prevalence of hepatitis C in patients with end stage renal disease, under renal replacement therapy either with hemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD), is higher than in the general population. The prevalence of hepatitis C in patients under dialysis, however, is unknown in Mexico. Thus, the major goals of the present study were to determine the prevalence of hepatitis C in our patients on dialysis, and the risk factors associated with it. METHODS: We performed a cross-sectional and comparative study in patients under dialysis in three hospital centers in the south of Mexico City. For every patient we evaluated: age, gender, etiology of the renal failure, modality and time in dialysis, transfusion and surgical history, serum albumin, aminotranferases, BUN, and serum creatinine. The presence of hepatitis C was assessed by ELISA II and qualitative RT-PCR in blood samples. In all patients diagnosed as having hepatitis C, RT-PCR to amplified part of the virus genome was also carried out in the dialysis fluid. RESULTS: We studied 235 dialysis patients that were classified according to their dialysis modality in: 132 patients under CAPD, 17 under CAPD and history of HD (PD/HD) and 86 under HD. The time under dialysis was different between the study groups: CAPD 29.6 +/- 22.3 months, PD/HD 39 +/- 42.3 and HD 14.2 +/- 15.6 (p < 0.01). The presence of hepatitis C was detected in 24 of the 235 patients, for a global prevalence of 10.2%. In no case was viral RNA found in the dialysis fluid. The prevalence varied, however, according to the type of dialysis. It was in the CAPD group 4.5%, 12.7% in the HD group, and 41.1% in the PD/HD group (p < 0.001). The multivariate analysis showed that the risk factors for hepatitis C are transfusions before the year of 1991 (Odds Ratio = 6.4), and history of hepatitis (OR = 4.3). Since less patients are seen with transfusions before 1991, we constructed another model in which this variable was excluded. This new multivariate model showed that history of surgery (OR = 4.4), the use of HD as the dialysis modality (OR = 3.5), and prolonged time under dialysis (OR = 1.01) were all significantly associated with the presence of hepatitis. DISCUSSION: Our results show that the prevalence of hepatitis C is lower in our patients that the prevalence reported by many others (average of other countries 18.5%). Since we found a higher prevalence in HD than in CAPD, even with the lower time under dialysis in the HD group, it is possible that our lower overall prevalence is secondary to the fact that CAPD is the most frequent mode of dialysis in our country. We observed the highest prevalence in the PD/HD group, that is probably due to longer exposure to the risk factors. The association with transfusions before 1991 indicates that the infection was acquired in some patients before dialysis was started. Our results showed that the CAPD is the dialysis technique with lower risk of hepatitis C infection.

Adult↗
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[Clinical course and prognostic factors in lupus nephropathy].

BACKGROUND: The present study was designed to know the clinical course of lupus nephritis and the risk factors associated with the development of end stage renal disease. METHODS: This a retrospective study performed in a cohort of 154 patients with biopsy proven lupus nephritis that were seen in our hospital between 1984 and 1990. The clinical records of all patients were reviewed in order to collect the following information at the time of the biopsy: age, sex, number and type of lupus criteria according with the American College of Reumathology, mean arterial pressure, serum creatinine, BUN, and albumin, as well as urinary protein excretion. The follow up was registered from the day the biopsy was performed to one of the following end points: end stage renal disease (defined as requirement of chronic dialysis), death or the end of study. All biopsies were analyzed by light microscopy to obtain the hystological subtype of lupus nephritis (WHO classification) and when type IV was diagnosed, the activity and chronicity indexes were also assessed. Kaplan-Meier survival tables were constructed. The association of clinical and laboratory variables with the development of end stage renal disease was obtained by log rank analysis. Variables obtained as significant were used to evaluate their individual impact using either the Cox multivariate proportional hazard method. RESULTS: Follow up was complete in 144 patients with a follow up time of 68 +/- 38 months. Ninety three patients were female with mean age of 28 +/- 9 years. At the time of the biopsy, renal manifestations had been present for 35 +/- 38 months and the number of lupus criteria per patient were 4 +/- 1. The clinical picture at the time of the biopsy was: nephrotic syndrome in 60%, non nephrotic proteinuria in 40%, and nephritic syndrome in only 2%. The hystological type of lupus nephritis was: I in 2%, II in 8%, III in 6%, IV in 71% and V in 11%. At the end of the study 28 patients developed end stage renal disease. For the whole group the survival of renal function was 85% at 70 months and 70% at 140 months. All, but one patient that developed end stage renal disease exhibited type IV nephropathy. In this subpopulation the mean activity and chronicity indexes were 8.5 +/- 3.5 and 3.1 +/- 2.4, respectively. By multivariate analysis the strongest predictors of end stage renal disease were the serum creatinine at the time of the biopsy, chronicity index, and age. The higher the serum creatinine and chronicity index at the time of biopsy, the higher the probability of developing end stage renal disease. CONCLUSIONS: We conclude that the clinical course of lupus nephritis in our population is similar to that seen in other series. The variables indicating advanced renal disease, such as high serum creatinine and chronicity index, were the strongest predictors of end stage renal disease.

Adult↗
PubMedDate not supplied

[Viral C hepatitis in patients with end stage renal disease. II. Viral genotypes].

BACKGROUND: The hepatitis C virus infection is highly prevalent in patients on chronic dialysis. There are more than 10 variants of the hepatitis C virus, with 55 to 72% of identity among them at the amino acid level. However, we do not know the specific genotype in dialysis patients in Mexico. Thus, the aim of the present study was to know the specific genotypes of the C virus in infected dialysis patients, to know the distribution of genotypes in the different dialysis techniques and to know the relation between genotype and hepatic disease stage. METHODS: We performed a prospective, transversal and comparative study in patients in dialysis in three hospital centers in the south of Mexico City. The presence of C-type hepatitis infection was assessed by ELISA II and qualitative RT-PCR in blood samples. The genotype of the hepatitis C virus was determined by analysis of the restriction pattern of the RT-PCR product using Mva I, Hinf I, BstU I and ScrF I restriction enzymes. Variables analyzed were: age, gender, etiology of renal failure, kind and time in substitutive therapy, transfusion and hepatitis history, liver function test, blood urea, serum creatinine and blood cell count. RESULTS: We studied 235 dialysis patients that were divided following their dialysis modality into: 132 in continue ambulatory peritoneal dialysis (CAPD), 17 in CAPD, but with history of hemodialysis (PD/HD) of at least one month and 86 on hemodialysis (HD). The hepatitis infection was detected in 24 of the 235 patients (CAPD = 4.5%, PD/HD = 41.1% and HD = 12.7%; p < 0.001). The most common genotype was 1B (12/24), followed by 1A and 2A (4/24 each one), and finally by 2B and 2C (2/24 each one). We detected no patients with genotypes 3 to 6. The patients with 2A genotype were older than those infected with 1A (p < 0.05). History of surgery, transfusions, and hepatitis was similar in all genotypes. Finally the time in dialysis was longer in patients with 2A genotype than others (2A = 60.5 +/- 71.5 months, vs. 1A = 11.5 +/- 11.3, 1B = 26 +/- 26.4 y 2B/C = 17.5 +/- 13.4), but the difference did not reach statistical significance. The genotype distribution between dialysis techniques showed that 1B genotype was the most frequent in all modalities. The 1A genotype was present in similar proportions in patients of the three dialysis groups, the 2C genotype was present only in patients with CAPD. Finally, the 2B was only found in hemodialysis patients. DISCUSSION: The assessment of viral genotype revealed that 1B is the most common genotype in patients on chronic dialysis in Mexico City. The fact that the 1B and 1A genotypes were the most common types in our dialysis population suggest that transmission was similar to the general population, that is, probably by blood transfusions.

Adult↗
PubMedDate not supplied

Quantification and characterization of protein loss in continuous ambulatory peritoneal dialysis.

BACKGROUND/AIMS: Dialysate protein loss is involved in the etiology of hypoalbuminemia and malnutrition on CAPD. There is no information regarding the peritoneal transport of proteins in neither Mexican nor LatinAmerican CAPD patients. Therefore, the aim of this study was to quantify and characterize the peritoneal membrane transport of albumin (Alb), IgG, IgA, and IgM in CAPD patients. In addition, factors associated to protein losses were investigated. METHODS: Thirty-seven CAPD patients were randomly selected and subjected to a standard peritoneal equilibration test (PET). Alb, IgG, IgA, and IgM were measured during the PET in both serum and dialysate. RESULTS: Dialysate IgM was not detected with the employed nephelometry method. A significant continuous and gradual increasing pattern in Alb, IgG and IgA losses was observed throughout the PET. During the PET, patients with the fastest transport type displayed the lowest serum concentration of Alb (but not Igs) and the greatest dialysate loss of all the assayed proteins. The strongest predictor for Alb, IgG, and IgA losses was peritoneal transport rate in both the univariate and multivariate analyses. CONCLUSIONS: Peritoneal Alb, IgG, and IgA losses in Mexican CAPD patients are mainly dependent on peritoneal transport rate and dialysate dwell-time.

Adult↗
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[Viral hepatitis C in patients with terminal chronic renal insufficiency. III. Viral quantification].

BACKGROUND: We have previously shown that the prevalence of hepatitis associated with the hepatitis C virus (HCV) in patients with end stage renal disease in our institution is 10.2%. However, quantification of viral RNA in plasma and its relation with clinical variables has never been studied in our patients. Thus, the aim of the present work was to quantify the HCV viral load in patients with ESRD in dialysis, and to correlate these values with the dialysis modality and the viral genotype. METHODS: We performed a transverse, prospective and comparative study in patients with HCV infection in hemodialysis, continuous ambulatory peritoneal dialysis and patients in peritoneal dialysis, but with history of hemodialysis. Viral load was quantified with RT-PCR by using a commercial kit known as Amplicor HCV 2.0. Clinical variables studied were: age, gender, end stage renal disease etiology, modality and time in dialysis, transfusions, serum albumin, aminotransferases, blood urea nitrogen, and serum creatinine. RESULTS: Twenty four patients in dialysis with HCV infection entered into the study. Of these patients, 25% were on peritoneal dialysis, 29% on peritoneal dialysis with history of hemodialysis, and 46% were in hemodialysis. The average viral load (copies x 10(6)/mL) was 1.41 +/- 3.01. Viral load was lower in patients on peritoneal dialysis than in patients treated, or with history of hemodialysis (0.20 +/- 0.12 vs 2.04 +/- 0.88; p < 0.05). We observed no differences in viral load among patients with different viral genotypes. DISCUSSION: The average viral load of our patients in dialysis is lower than the levels usually observed in hepatitis C infected patients without end stage renal disease. The lower viral load in patients treated with peritoneal dialysis, and no history of hemodialysis, probably denotes lower risk of chronic liver disease in these subpopulation.

Adult↗