Search PubMed⌕ Search

Biomedical subjects

M C Díaz

Publications and source records attributed to M C Díaz.

At least 19 recordsLinked to original sources
PubMed2005

Comparative study between living and cadaveric donors in pediatric liver transplantation.

UNLABELLED: We examined whether the results in living-related hepatic transplantation (LRLT) are better than those from a cadaveric donor (CDLT). MATERIAL AND METHODS: The last 27 consecutive LRLT, performed from 1998 to 2005, were compared with 27 CDLT matched for age, weight, date, and diagnosis. Grafts in LRLT group were left lateral segment (n = 22), left lobe (n = 3), and right lobe (n = 2). In the CDLT group, the grafts were split in situ (n = 10), hepatic reduction (n = 9) and whole liver (n = 8). We analyzed the actuarial survivals (grafts and children), retransplantation, primary nonfunction, initial graft malfunction (liver enzymes >2000 U/L), surgical complications, rejection, and resource consumption. RESULTS: Patient survivals at 6 months, 1 year, and 5 years were 100%, 96%, and 96% in LRLT and 100%, 100%, and 100% in CDLT (P = NS). Graft survivals were 93%, 89%, and 89% versus 96%, 96%, and 96%, respectively (P = NS). Complications were biliary complications (LRLT, 25% vs CDLT, 3%; P = .021); portal vein thrombosis (LRLT, 7% vs CDLT, 3%; NS), and hepatic artery thrombosis (LRLT, 0% vs CDLT, 3%; NS). The overall incidence of acute rejection was slightly higher (NS) in LRLT (LRLT, 18% vs CDLT, 11%; NS). Liver enzyme levels were higher in the CDLT group, but initial malfunction rate was not statistically different. Regarding resource consumption: blood product needs were higher in LRLT (P < .05) and hospital stay and ICU stay were longer, although not significantly, among LRLT. CONCLUSIONS: The results in LRLT among children are similar to those obtained in CDLT. We found a trend towards less initial graft malfunction in LRLT. Blood product needs were higher in LRLT. Hospital and ICU stay were longer, but not significantly different in LRLT. The benefits of LRLT are saving a scarce resource: a cadaveric donor liver graft.

Body Weight↗
PubMed2003

[Prognostic factors in pediatric liver transplantation. Multivariate analysis].

AIM: To analyze independent risk factors associated with poor graft and patient survival in a series of 292 pediatric liver transplants (PLT) performed in 234 children during a 15 years period. MATERIAL AND METHODS. 1. Univariate graft and patient survival analysis in 45 variables related to pretransplant patient status, surgical technique and donor conditions. 2. Variables found with univariate analysis to be associated with outcome were entered into a stepwise backward proportional hazard model (Cox), to determine independent prediction of outcome. RESULTS: 11 variables influence the graft survival: recipient age, z-score recipient height, UNOS status, recipient and donor weight, transplant for immune hepatitis, platelet transfusion during the transplant, blood index > 4 during the surgery, type of arterial reconstruction, retransplantation and era of the transplant (first er: 1986-1990; 2nd. era: 1991-1995; 3rd. era: 1996-2000). Four of those variables are independent in the multivariate analysis: UNOS 1 status (Odds Ratio, OR = 2.82, 95% confidence interval = 1.36-5.85), recipient < 3 years (OR = 3.76, 95% CI = 2.13-6.63), transplants for autoimmune hepatitis and era (OR of first and second versus third era respectively 3.93 and 2.81). The independent variables influencing the patient survival were: children receiving more than one graft children less than 3 years old and transplant era. CONCLUSIONS: Liver transplant in small children is associated with an increased risk of graft loss and patient dead. The experience of the hospital in pediatric liver transplantation improves the results, particularly in small children.

Adolescent↗
PubMed2002

Effect of nutrient intake on the development of the somatotropic axis and its responsiveness to GH in Holstein bull calves.

We investigated the effect of increasing nutrient intake on the responsiveness of the GH/IGF-I system in calves fed a high-protein milk replacer. Fifty-four Holstein bull calves were fed one of three levels (low, medium, and high; n = 18 per treatment) of a 30% crude protein, 20% fat milk replacer to achieve target rates of gain of 0.50, 0.95, or 1.40 kg/d, respectively, for low, medium, and high. Six calves per treatment were slaughtered at approximately 65, 85, and 105 kg BW. Additionally, six calves were slaughtered at 1 d of age to provide baseline data. Plasma aliquots from blood samples collected weekly were analyzed for IGF-I, insulin, glucose, NEFA, and plasma urea nitrogen (PUN). Plasma IGF-I and insulin, measured weekly, increased (P < 0.001) with greater nutrient intake from wk 2 of life to slaughter. Plasma glucose and NEFA also increased (P < 0.05) with nutrient intake. In addition, each calf underwent a GH challenge beginning 4 d before the scheduled slaughter. Plasma from blood collected before the first GH injection and 14 and 24 h after the third injection was analyzed for IGF-I and PUN. Response to challenge, calculated as the absolute difference between the prechallenge and 14-h postchallenge plasma IGF-I concentrations, was significant in calves on all three treatments. Plasma urea nitrogen was not different among treatments as measured weekly but decreased (P < 0.001) following GH challenge in all calves. Results of ribonuclease protection assays showed increased expression of hepatic mRNA for GH receptor 1A and IGF-I with increased intake. The amounts of GH receptor and IGF-I mRNA in muscle and adipose, however, were not affected by intake. In summary, plasma IGF-I was elevated in calves with increased nutrient intake, and the elevations in plasma IGF-I following short-term administration of GH were significant in all calves by 65 kg BW. Data demonstrate that in well-managed milk-fed calves the somatotropic (GH/IGF-I) axis is functionally coordinated and sensitive to nutrient intake and GH.

Animals↗
PubMed2002

[Isotopic renal study in diabetic nephropathy].

UNLABELLED: This study aimed to evaluate the prognostic value of the kidney split function (KSF), the effective renal plasma flow (ERPF) and glomerular filtration rate (GF) in the evolution of diabetic nephropathy. MATERIAL AND METHODS: 125 patients (IDDM:10, NIDDM:115), including 62 men, ages 18-84 years, were studied. In all cases GF (Cr 51 EDTA), ERPF (131I-hippuran), kidney split function (obtained from the 99mTc-MAG3 renogram) and basal serum creatinine (SC) were evaluated at the beginning of the study and patients were clinically followed up for 5 years by SC. Ultrasound and/or intravenous digital angiography were performed in 120 patients. RESULTS: In patients with decreased ERPF (76 patients) the SC increased progresively during the 5 years, in both those with elevated PC (N = 54) as well as in those with normal baseline SC (n = 22). In patients with normal ERPF the SC did not change significantly during the study. An asymethric split function (KSF < 40% in one kidney) was found in the renogram of 42 patients; in 32 of them the ERPF was decreased. Of these, ulttrasonography was normal in 9, and vascular and/or obstructive pathology was demonstrated by ultrasonography or digital angiography in only 6 patients. CONCLUSION: The ERPF becomes altered earlier than serum creatinine in patients with diabetic nephropaty. ERPF and split function calculation, and FG seems to have higher prognostic value than ultrasounds in the management of diabetic nephropathy. Radionuclides seems to be an accurate test than the ultrasonography to detect renal function abnormalities in patients with diabetic and thus can be an examination of choice in these patients.

Adolescent↗
PubMed2002

[Systemic yeast infections in a general hospital. Correlation between study of susceptibility in vitro and patient survival to the fungal infection episode].

BACKGROUND: Fungi are important causal agents of nosocomial infections, that usually have high mortality rates. AIM: To evaluate the species distribution and susceptibility patterns of deep yeast infections in a General Hospital and to correlate those results with patient survival. MATERIAL AND METHODS: Twenty one strains (from five pediatric and 16 from adult patients) were studied. Antifungal Susceptibility Testing (AST) to Amphotericin B (Anfb), Fluorocytosine (5FC), Fluconazole (FZ) and Itraconazole (IZ) was performed according to the EUCAST document. Clinical data of patients was obtained and survival to the infection was recorded. RESULTS: C. albicans was isolated in 11 samples (52%), C. parapsilosis in three samples (14%), C. glabrata in two samples (9%), C. tropicalis in one sample (5%) and C. neoformans in four samples (19%). Twenty three percent of fungi were recovered at the Surgical Intensive Care Unit. The MICs ranged between 0.25 and 0.5 microgram/mL for Anfb; between 0.25 and 16 micrograms/ml for SFC, between 0.12 and 32 micrograms/mL for FZ and 0.015 and 0.5 microgram/mL for IZ. No association between antifungal susceptibility and patient survival was observed. CONCLUSIONS: C. albicans continues to be the most frequently isolated yeast, however, non-albicans species are an emergent group causing nosocomial infections. Surgical procedures are the main source of fungal infections in this sample.

Adult↗
PubMed2001

Chemotaxis, viability, and labeling stability of leukocytes labeled with (99m)Tc-exametazime stabilized with methylene blue.

UNLABELLED: The in vitro viability, chemotaxis, and labeling stability of leukocytes labeled using (99m)Tc-exametazime stabilized with methylene blue were evaluated and compared with those obtained using nonstabilized (99m)Tc-exametazime. METHODS: Two identical leukocyte populations, from 30 healthy donors, were labeled simultaneously using freshly prepared and 2-h-old stabilized (99m)Tc-exametazime. The following quality control techniques were performed on each labeled leukocyte sample: eosin Y staining, chemotaxis radioassay, and labeling stability at 2 h after labeling. RESULTS: Eosin Y staining showed a cell viability of at least 98% in all samples, without a significant statistical difference between the populations. Chemotactic indices obtained with leukocytes labeled with freshly prepared, unstabilized (99m)Tc-exametazime were statistically greater than those obtained using (99m)Tc-exametazime stabilized with methylene blue (z = 2.41; P<0.02). Labeling stability at 2 h after labeling was the same for both populations. CONCLUSION: The use of (99m)Tc-exametazime stabilized with methylene blue for leukocyte radiolabeling does not affect either cell membrane integrity or labeling stability but can cause a decrease in the cell chemotactic capacity that discourages its clinical use.

Cell Survival↗
PubMed2000

Intracellular distribution of GABA in the rat anterior pituitary. An electron microscopic autoradiographic study.

We studied the internalization and intracellular distribution of [3H] GABA in rat anterior pituitary cells. Electron microscopic autoradiography of anterior pituitary fragments or dispersed pituitary cells incubated with [3H] GABA showed that lactotrophs and, to a lesser extent, somatotrophs were the only cells that contained radioactive grains. Grain density analysis performed on dispersed pituitary cells after a pulse-chase experiment (10 min pulse and then change to a medium without radioactive GABA for various periods up to 2 h) revealed that GABA internalized by lactotrophs was distributed in various intracellular membranous organelles. Of the cell compartments examined, plasma membrane, Golgi apparatus, mitochondria and secretory granules had different time-dependent labeling patterns. The highest grain density values were associated with plasma membrane (at the first chase time) and the Golgi apparatus. Mitochondria and secretory granules also showed significant grain density values. A similar pattern of distribution was observed when fragments of prolactin-secreting pituitary adenomas were incubated with [3H] GABA. These results provide morphological data on the cellular specificity and intracellular distribution of GABA in anterior pituitary cells.

Animals↗
PubMed2000

Effects of substrate, water activity, and temperature on growth and verrucosidin production by Penicillium polonicum isolated from dry-cured ham.

Penicillium polonicum, a common mold on dry-cured meat products, is able to produce verrucosidin, a potent neurotoxin. The ability of P. polonicum isolated from dry-cured ham to grow and produce verrucosidin from 4 to 40 degrees C at water activities (a(w)) of 0.99, 0.97, and 0.95 on malt extract agar (MEA) and a medium made up with meat extract, peptone, and agar (MPA) was evaluated. Verrucosidin was quantified by high-pressure liquid chromatography and mass spectrometry. P. polonicum was able to grow on MEA and MPA at all the a(w) values tested from 4 to 37 degrees C but not at 40 degrees C. The optimal environmental conditions for growth were 20 degrees C, 0.99 a(w) on MEA and 20 to 25 degrees C, 0.97 a(w) on MPA, but the highest amount of verrucosidin was obtained at 25 degrees C, 0.99 a(w) in both media. No direct correlation between extension of mold growth and verrucosidin production was found. Temperature appears to be the most important factor ruling mycelial growth, whereas verrucosidin accumulation is mostly influenced by a(w). However, analysis of variance of the data showed that there was a complex interaction among all the environmental factors (medium, temperature, and a(w)) that significantly (P < 0.0001) affected growth and verrucosidin production. The reduction of a(w) to intermediates values of 0.95 has a stronger effect on growth on MEA than on MPA. Given that the meat-based medium proved to be an appropriate substrate for the biosynthesis of verrucosidin by P. polonicum, the ability of this mold to produce the toxin on meat products should be established.

Animals↗
PubMed2000

[Kasai operation in the age of liver transplantation. Healing or merely palliative technique?].

AIM: To assess the results of portoenteroanastomosis (PEA) and liver transplantation (OLT) in extrahepatic biliary atresia (EHBA). METHODS: Out of a series of 148 EHBA, 92 cases primarily treated by us were selected. Survival with the native liver (end point = death or OLT) and its relationship with the age at PEA, type of EHBA, ductal size and bile flow restablishment were assessed. Patient survival was compared in those patients who had access to OLT when needed (Group I, n = 69) and those in whom only PEA was available (Group II, n = 23). (OLT program started in january 1986). RESULTS: At the end of follow-up, 32 children are alive with their native livers, 22 died and 38 had OLT. 40/85 patients who underwent PEA had complete restablishment of bile flow (47%). The no failure rate (survival of the native liver) at 1, 5, 10 and 20 years, was 91%, 49%, 38% and 21%, respectively. Bile flow restablishment was the only predictor significantly associated with good prognosis (survival of native liver at 5, 10 and 20 years of 89%, 86% and 51%, respectively). Differences in survival were significant (p < 0.001) between patients in groups I and II at 1 year (92% vs 74%), 5 years (78% vs 35%), 10 years (76% vs 30%) and 20 years (76% vs 30%). CONCLUSIONS: Bile flow restablishment after PEA can be obtained in experienced centers in about 50% of cases of EHBA. The combined and sequential use of PEA and OLT allows excellent long-term survival in EHBA.

Biliary Atresia↗
PubMed1999

NMDA receptor-mediated control of GABA release from neurointermediate lobes of female and male rats.

The effect of glutamate (GLUT) and its ionotropic receptor agonists on K(+)-evoked GABA release from the neurointermediate lobe (NIL) was investigated in diestrus, ovariectomized, ovariectomized-estrogenized female rats and intact male rats. GLUT and N-methyl-D-aspartate (NMDA) increased K(+)-evoked GABA release from the NIL in all the experimental groups. This stimulatory effect of NMDA was blocked by specific NMDA receptor antagonists but not by non-NMDA receptor antagonists. However, kainate did not modify evoked GABA release from the NIL in any of these groups. Neither GLUT nor NMDA modified nitric oxide synthase activity. These results indicate that GLUT, acting through NMDA receptors, stimulates evoked GABA release from the NIL of female and male rats. This effect is not influenced by gonadal status and does not appear to be mediated by nitric oxide production.

2-Amino-5-phosphonovalerate↗
PubMed1999

A high index of suspicion: the key to an early diagnosis of Wilson's disease in childhood.

BACKGROUND: To study the clinical features of Wilson's disease in childhood. METHODS: Retrospective review of the clinical, laboratory, and histologic features and prognosis of Wilson's disease in 26 Spanish children. RESULTS: The first medical visit, at age 9.8+/-3.4 years (range, 4-16 years), was prompted by liver dysfunction detected accidentally (61%), symptoms of liver disease (27%), family screening (8%), and extrapyramidal symptoms and personality changes (4%). There were laboratory data of hepatic failure in 27%. All copper metabolism test results (total serum copper, 24-hour urine excretion, serum ceruloplasmin) were abnormal in 62%, two in 27%, and one in 11%. All patients in whom extrahepatic involvement was found at diagnosis had severe liver disease. Histologic findings were portal fibrosis with steatosis (29%), cirrhosis (21%), portal fibrosis (17%), chronic active hepatitis (17%), and minimal changes or normality (17%). Penicillamine was administered to all but one patient. Four children underwent liver transplantation, three of them having received penicillamine for 12, 45, and 70 days. Three other patients recovered from liver failure after 1 year of treatment with penicillamine. After a follow-up of 4.5+/-3.3 years, all the children survived. Penicillamine caused severe toxicity in one patient. CONCLUSIONS: Wilson's disease in childhood is generally detected by maintaining a high suspicion of liver disease in patients who have no or nonspecific hepatic symptoms. Kayser-Fleischer ring is rare in childhood. Drug therapy is effective and well tolerated, even in some cases of hepatic insufficiency.

Adolescent↗
PubMed1999

[Antimicrobial resistance of agents causing urinary tract infections in 11 Chilean hospitals. PRONARES project].

BACKGROUND: The computer program WHONET generates a common database to analyze local or general antimicrobial resistance of bacteria. A surveillance of agents causing urinary tract infections in Chile has been performed using this program. AIM: To report the results after 12 months of urinary tract infection agent surveillance. MATERIAL AND METHODS: Since November, 1997, a surveillance of in vitro antimicrobial resistance, using agar diffusion techniques, has been performed in 20 to 40 bacterial strains per month, isolated from 11 hospitals in the country. Results have been analyzed using WHONET program. RESULTS: In first 12 months, 3144 strains, 1625 coming from outpatients, have been studied. Seventy four percent of isolated strains were E coli, 19% were other enterobacteria, 4.1% were non fermenting bacilli and 2.1% were Gram (+) cocci. Sixty five percent of E coli strains were resistant to ampicillin, 11% to cefazolin, 2.5% to cefuroxime, 19% to ceftriaxone, 9% to ceftazidime, 4.2% to gentamicin 1.3% to amikacin, 5.6% to ciprofloxacin, 8.4% to grepafloxacin, 4.3% to nitrofurantoin and 43% to trimeproprim/sulphamethoxazole. Eighty two percent of other enterobacteria strains were resistant to ampicillin, 45.5% to cefazolin, 33.5% to cefuroxime, 26.6% to ceftriaxone, 21.5% to ceftazidime, 30.3% to gentamicin 17.2% to amikacin, 21% to ciprofloxacin, 16.3% to grepafloxacin, 48.2% to nitrofurantoin and 44.6% to trimeproprim/sulphamethoxazole. There were differences in betalactamic resistance among hospitals. CONCLUSIONS: Noteworthy is the high resistance rates to third generation cephalosporins, evidenced when the new cutoff values for E coli and Klebsiella spp are used. This national surveillance provides updated information on antimicrobial resistance of agents causing urinary tract infections.

Chile↗
PubMed1998

Tacrolimus for steroid-resistant liver rejection in children.

Eighteen pediatric liver transplant recipients were converted from cyclosporine-based immunosuppression to tacrolimus for refractory rejection episodes affecting 21 grafts. Before conversion, steroid boluses were applied to all episodes followed by OKT3 monoclonal antibodies in 3 of them. Baseline biopsy showed cellular rejection in 18 patients and ductopenia in 3 cases. Thirteen episodes initiated within the first 2 postoperative weeks, and 8 occurred beyond the 21st day. A previous steroid-responsive episode of rejection was noted in 4 patients. Tacrolimus was administered by the oral route to obtain trough blood levels in the range 6-15 ng/ml. Reversal of rejection was obtained in 15 patients (71.4%). Complete normalization of liver function tests was achieved in 10 out of 12 patients who were followed for more than 6 months. A refractory evolution affected 6 patients (28.5%). Significant factors predictive for tacrolimus-resistant rejection were identified as ductopenia on baseline biopsy, previous episodes of acute rejection, late onset rejection (beyond 21st posttransplant (day), and a longer time of evolution of rejection prior to conversion.

Adolescent↗
PubMed1997

Vasoactive intestinal peptide (VIP) mediates the effect of estrogens on the dopaminergic tone in the hypothalamic-pituitary axis of ovariectomized (OVX) rats.

The role of vasoactive intestinal peptide (VIP) in the regulation of dopamine (DA) concentration in mediobasal hypothalamus (MBH), posterior and anterior pituitary of ovariectomized (OVX) estrogenized rats was studied using passive immunization against VIP with a specific antiserum (a-VIP). Chronic estradiol administration decreased DA concentration in MBH, and in posterior and anterior pituitary, compared to OVX control rats. DA tissue concentration increased following a-VIP administration to control and estrogenized OVX rats. In vitro study of VIP and a-VIP on DA release from MBH in chronically estrogenized OVX rats showed that estrogens decreased DA evoked-release from MBH;a-VIP increased DA evoked-release from MBH of control OVX and estrogenized rats. VIP decreased DA evoked-release from MBH of OVX rats, but had no effect on estrogenized rats. VIP decreased DA tissue concentration in MBH of OVX control but not of estrogenized rats. It is suggested that VIP decreases DA synthesis and release from hypothalamic neurons in female rats, and that VIP partially mediates the inhibitory effect of long-term estrogen administration on DA release from MBH.

Animals↗
PubMed1996

Neurokinin A affects the tubero-hypophyseal gabaergic system.

We have studied the in vitro effects of neurokinin A (NKA) on anterior pituitary GABA concentration and GABA release from the mediobasal hypothalamus and the neurointermediate lobe of male and ovariectomized female (OVX) rats. NKA significantly decreased the anterior pituitary GABA concentration, while the presence of a specific anti-NKA serum in the incubation medium increased the GABA concentration in this gland. By contrast, NKA did not modify basal or K(+)-evoked GABA release from the mediobasal hypothalamus of male or OVX rats. However, NKA decreased basal and K(+)-evoked GABA release from the neurointermediate lobe. Since GABA inhibits both prolactin (PRL) secretion from the anterior pituitary and the release of several putative PRL-releasing factors from the neurointermediate lobe, the decrease in anterior pituitary GABA concentration and the reduction in tubero-hypophyseal GABAergic activity induced by NKA may contribute to the stimulatory effect of this peptide on PRL secretion.

Animals↗
PubMed1996

Growth and height in children after liver transplantation.

To assess the linear growth after liver transplantation, height curves were constructed for 45 children who underwent liver transplantation at the Children's Hospital "La Paz", Madrid, and were followed for more than 2 years. The prednisolone dose was progressively tapered and switched to alternate-day administration at 12 months. Growth was severely impaired during daily steroid therapy but the mean growth rate normalized in the second year and a significant improvement was observed in successive years. Observations over a long period revealed fluctuating growth rates under stable or decreasing doses of prednisolone on alternate-day administration. Beyond the first year, some annual periods of abnormal growth rate occurred in 57% of the children. Marginally better posttransplantation growth was observed in children transplanted for intrahepatic cholestatic diseases. The prednisolone dose did not correlate with growth rate. In the long term, short stature was highly prevalent due to an accumulation of factors: previous disease, daily prednisolone period, inconstant growth rate under alternate-day steroid therapy, and pubertal delay.

Adolescent↗