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Biomedical subjects

A Aguilera

Publications and source records attributed to A Aguilera.

153 records · Page 9Linked to original sources
PubMedDate not supplied

Risk factors responsible for ultrafiltration failure in early stages of peritoneal dialysis.

OBJECTIVE: To define risk factors for ultrafiltration failure (UFF) during early stages of peritoneal dialysis (PD). DESIGN: Retrospective analysis of a group of patients whose peritoneal function was prospectively followed. SETTING: A tertiary-care public university hospital. PATIENTS: Nineteen of 90 long-term PD patients required a peritoneal resting period to recover UF capacity: 8 had this requirement before the third year on PD (early, EUFF group) and 11 had a late requirement (LUFF group). The remaining 71 patients, those with stable peritoneal function over time, constituted the control group. MAIN OUTCOME MEASURES: Peritoneal UF capacity under standard conditions (monthly) and small solute peritoneal transport (yearly). RESULTS: None of the conditions appearing at the start of PD or during the observation period could be definitely identified as the cause of UFF. There were no differences in characteristics between the EUFF group and the other two groups, except for the higher prevalence of diabetes in the EUFF group. Residual renal function (RRF) declined in all three groups during the first 2 years, with rapid loss during the third year in the EUFF group. This rapid loss in RRF was coincident with UFF. Peritoneal solute and water transport at baseline was similar in the three groups. After 2 years on PD, individuals in the EUFF group showed a significantly lower UF and higher creatinine mass transfer coefficient values than those in the LUFF group. Diabetic patients in the control group showed remarkable stability in UF capacity over time. During the second year on PD, requirement for increases in dialysate glucose concentration was 3.4 +/- 0.5% in the LUFF group, but as high as 25.5 +/- 24.2% in the EUFF group. The accumulated days of active peritonitis (APID, days with cloudy effluent) were similar for the three groups after 1, 2, and 3 years on PD. Interestingly, diabetic patients in the control group showed an APID index significantly lower than the overall EUFF group. Diabetics in the control group also had significantly lower APID versus nondiabetics in the control group (p = 0.016). CONCLUSIONS: Our findings suggest that certain patients develop early UFF type I. Diabetic state and a higher glucose requirement to obtain adequate UF suggest that glucose on both sides of the peritoneal membrane could be responsible. The mechanisms for this higher requirement remain to be elucidated. The identification of a larger cohort of these early UFF patients should lead to a better exploration of the primary pathogenic mechanisms.

Hemodiafiltration↗
PubMedDate not supplied

Uremic anorexia: a consequence of persistently high brain serotonin levels? The tryptophan/serotonin disorder hypothesis.

Anorexia is a frequent part of uremic syndrome, contributing to malnutrition in dialysis patients. Many factors have been suggested as responsible for uremic anorexia. In this paper we formulate a new hypothesis to explain the appetite disorders in dialysis patients: "the tryptophan/serotonin disorder hypothesis." We review current knowledge of normal hunger-satiety cycle control and the disorders described in uremic patients. There are four phases in food intake regulation: (1) the gastric phase, during which food induces satiety through gastric distention and satiety peptide release; (2) the post absorptive phase, during which circulating compounds, including glucose and amino acids, cause satiety by hepatic receptors via the vagus nerve; (3) the hepatic phase, during which adenosine triphosphate (ATP) concentration is the main stimulus inducing hunger or satiety, with cytokines inhibiting ATP production; and (4) the central phase, during which appetite is regulated through peripheral (circulating plasma substances and neurotransmitters) and brain stimuli. Brain serotonin is the final target for peripheral mechanisms controlling appetite. High brain serotonin levels and a lower serotonin/dopamine ratio cause anorexia. Plasma and brain amino acid concentrations are recognized factors involved in neurotransmitter synthesis and appetite control. Tryptophan is the substrate of serotonin synthesis. High plasma levels of anorectics such as tryptophan (plasma and brain), cholecystokinin, tumor necrosis factor alpha, interleukin-1, and leptin, and deficiencies of nitric oxide and neuropeptide Y have been described in uremia; all increase intracerebral serotonin. We suggest that brain serotonin hyperproduction due to a uremic-dependent excess of tryptophan may be the final common pathway involved in the genesis of uremic anorexia. Various methods of ameliorating anorexia by decreasing the central effects of serotonin are proposed.

Amino Acids↗
PubMedDate not supplied

Diverticular disease and treatment with gastric acid inhibitors do not predispose to peritonitis of enteric origin in peritoneal dialysis patients.

OBJECTIVE: Enteric peritonitis (EP) is an infrequent complication of peritoneal dialysis (PD), with severe consequences for peritoneal membrane viability and patient outcome. Factors such as diverticular disease and gastric acid inhibitors have been implicated in its appearance. We investigated several risk factors, including those mentioned below, that can influence the development of EP. DESIGN: Retrospective cross-sectional study. SETTING: Tertiary-care public university hospital. PATIENTS: Fifty-seven PD patients treated in our PD unit during August 1998. MAIN OUTCOME MEASURES: A barium enema was performed on 50 of the 57 patients (the remaining 7 patients refused it) in order to exclude the presence of diverticulosis. All episodes of peritonitis occurring in those patients, including EP, were registered. Enteric peritonitis was defined as that caused by gram-positive, gram-negative, or fungus micro-organisms that colonized the intestinal tract, excluding episodes secondary to genitourinary tract or peritoneal catheter exit-site infections. RESULTS: Twenty-four patients showed diverticular disease in the barium enema, but only 5 of them (21%) had any EP episode. Five of the 26 patients with no diverticula (19%) had EP. Fifty-five episodes of peritonitis were reported in 21 patients; 15 episodes of EP (27.3% of all) developed in 11 patients. Seven of the 11 patients (64%) required peritoneal catheter removal and 3 of them (27%) finally were transferred to hemodialysis due to consequences of the EP episode. Logistic regression analysis did not find any of the independent variables analyzed (age, sex, time on PD, type of PD, peritoneal transport parameters, presence of polycystic kidney disease, constipation or diverticulosis, or treatment with gastric acid inhibitors, or phosphate-binding agents) to be risk factors for developing EP. CONCLUSIONS: Neither diverticulosis nor treatment with gastric acid inhibitors seem to be risk factors for developing peritonitis of enteric origin in PD patients. This type of peritonitis has to be promptly identified and treated in order to diminish the high frequency of peritoneal catheter removal and PD dropout due to such episodes.

Adolescent↗
PubMedDate not supplied

Morphologic alterations of experimental rubella syndrome in rabbits.

Rabbits were used as experimental subjects for study of circulation of the rubella virus in intrauterine life and of the histopathological alterations produced by inoculation of wild strains during the first third of pregnancy. Fetuses taken in the 14th, 21st and 28th days of pregnancy, as well as 1-month-old and 5-month-old animals were used for the embryologic and virological studied. Of the 20 animals infected, 90% presented histopathological lesions. The most affected viscera being the liver (80%), heart (60%). kidney (30%) and the crystalline lens (5%). Virological study was made of only 11 animals, from which 100% viral isolation was obtained, with similar results between viral isolation and the appearance of lesions in the liver (72%) and the kidney (44%), while a marked discrepancy in the virus-lesion relationship was found for the heart (33%) and the crystalline lens (77%). We conclude that the etiopathogeny of the syndrome cannot be explained only by direct action of the virus on the fetal tissues, but must be multiple.

Animals↗
PubMedDate not supplied

Histopathological study of human placenta in women infected with rubella virus during pregnancy.

A histopathological and virological study is carried out on a group of placentae in the second trimester of pregnancy, obtained during the 1974 rubella epidemic in Cuba. The comparison between the positive and negative cases did not show characteristic lesions of the virus passage through the placenta, which does not coincide with the reports of other authors who generally consider these alterations as a result of this pathology. Eosinophilic intracytoplasmic granules were found in the Hofbauer cells, which should be studied by employing other techniques for accurate identification.

Female↗
PubMedDate not supplied

Association of HCV and HBV markers in Spanish HIV-seropositive patients in relation to risk practices.

BACKGROUND/AIMS: HBV, HCV, and HIV have some transmission routes in common. Viral liver disease is a leading cause of mortality in HIV-infected patients. The study was aimed at evaluating the prevalence of HBV and HCV markers in subjects with different risk practices for HIV infection. METHODOLOGY: A total of 699 subjects were studied Of these subjects, 517 were intravenous drug users (373 HIV-positive and 144 HIV-negative), 127 had heterosexual risk practice (66 HIV-positive and 61 HIV-negative), 31 had homosexual risk practice (all HIV-positive), 15 had post-transfusional HIV infection, and nine had HIV infection of unknown source. Patients with anti-HBc antibody were considered HBV-positive, and cases with anti-HCV antibodies were considered HCV-positive. RESULTS: Among patients with HIV infection, most intravenous drug users (79%) had markers of both HBV and HCV, compared with 20%, 11%, and 10% of cases infected by transfusional, heterosexual, and homosexual route, respectively (p < 0.001). Absence of both HBV and HCV markers was observed in most HIV-positive heterosexuals (62%) compared with 40% of post-transfusional cases, 32% of homosexuals and 4% of intravenous drug users (p: NS, p = 0.009, and p < 0.001, respectively). Isolated HBV-positivity was the most frequent pattern in HIV-infected homosexuals (58%), compared with 27% of post-transfusional, 21% of heterosexuals and 11% of intravenous drug users (p: NS, p < 0.001 and p < 0.001, respectively). HIV-negative intravenous drug users had a lower prevalence of HBV/HCV association than HIV-positive cases (p < 0.001). Isolated HCV-positivity was more frequent in HIV-negative than in HIV-positive intravenous drug users (27% vs. 6%, p < 0.001). In heterosexuals, isolated HBV-positivity was more prevalent in HIV-positive than in HIV-negative cases (21% vs. 7%, p = 0.04). CONCLUSIONS: HBV and HCV seroprevalence in HIV infected patients vary depending on the risk practice. This suggests a variable transmissibility depending on the route considered. Within the same risk practice, differences in HCV and HBV seroprevalence between HIV-positive and HIV-negative cases suggest that some factors associated with HIV infection may influence the rate of infection by HCV and HBV.

Adolescent↗
PubMedDate not supplied

[In vivo interactions of Rubella virus with peritoneal macrophages in immunized and non immunized rats].

The pathogenicity of rubella virus for macrophages of immune and non-immune rats was studied using not a natural route of inoculation and studying the sequence of morphologic changes in cells as well as virus growth in the peritoneal cavity, the development of viremia and the neutralizing antibody response against the infectious agent. Non-immune rats evidenced a possible development of cell immunity in the course of the process. Immune rats had acquired a cell immunity in addition to a specific secondary response manifested early at the beginning of infection.

Animals↗