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Biomedical subjects

C Díaz

Publications and source records attributed to C Díaz.

At least 37 records · Page 2Linked to original sources

[The value of waiting in spontaneous remission of recurrent tonsillitis without associated adenoid pathology].

In order to assess the rate of spontaneous remission in children with recurrent acute tonsillitis (RAT), we revised the pediatric patients who were seen between 1994 and 1999. For this purpose, 123 cases that were on the waiting list for tonsillectomy under the indication of RAT without associated adenoid disease were selected. Only 23 (18.7%) of the children who were included in the study were removed from the waiting list after a mean time of 9 months because of spontaneous remission of the disease. Thus, there is no justification for claiming that long waiting lists for tonsillectomy are frequently associated with spontaneous remission of RAT.

Acute Disease↗

Allelic polymorphism -491A/T in apo E gene modulates the lipid-lowering response in combined hyperlipidemia treatment.

BACKGROUND: Combined hyperlipidemia (CHL) is one of the dyslipidemias more frequently found in clinical practice, and lipid-lowering drugs are often necessary in its management. Some genetic loci have been associated with CHL expression, and some studies have shown modulation of drugs efficiency in the treatment of dyslipidemias by genetic polymorphisms. We have investigated whether common polymorphisms and mutations in the apolipoprotein (apo) E, lipoprotein lipase (LPL), and apo CIII genes influence atorvastatin or bezafibrate responses in patients with CHL. DESIGN: One hundred and sixteen subjects participating in the ATOMIX study (Atorvastatin in Mixed dyslipidemia) were randomized to treatment with either atorvastatin or bezafibrate. Apolipoprotein E genotype and common -491A/T and -219T/G polymorphisms in the apo E gene promoter region, Sst I polymorphism in the apo CIII gene (3238C/G), and D9N and N291S common mutations in the LPL gene were determined by polymerase chain reaction (PCR) and restriction enzyme digestion. RESULTS: Statistical analysis showed the influence of the -491A/T polymorphism in atorvastatin and bezafibrate treatments. Subjects carrying the -491T allele showed an increased LDL-cholesterol-lowering effect with atorvastatin compared with -491T allele noncarriers (-35% vs. -27%, P = 0.037). Subjects carrying the -491T allele, when on bezafibrate treatment, showed a lower triglyceride reduction compared with -491T allele noncarriers (-23% vs. -39%, P = 0.05). CONCLUSIONS: In our study, the -491A/T polymorphism in the apo E gene promoter region modulated the lipid-lowering efficiency of atorvastatin and bezafibrate in CHL patients. Such influence might explain some of the interindividual response variabilities observed for the two drugs, and could help in CHL management.

Adult↗

[Acute renal failure caused by cholesterol embolism in kidney transplantation from cadaver donor. Is the prognosis more favorable than in native kidneys?].

We present the case of a 47 years old women with a third cadaveric kidney transplant. After surgery, she had effective diuresis reaching a serum creatinine of 2.2 mgs% at 19 postoperative day. In the nest few days, the patient was oliguric with worsening of renal function. The ultrasound examination excluded urinary obstruction. With the suspicion of acute rejection, a renal biopsy was performed. The histopathological record disclosed cholesterol emboli with a widespread multifocal ischemic infarct and eosinophilic tubulointerstitial nephritis. The renal function deteriorated in the seven next days and peritoneal dialysis was carmedow. She then recovered diuresis with improvement of renal function, reaching at discharge a serum creatinine of 1.8 mgs%. The renal function remains stable after 3 years. We analysed the etiopathogenic factors of this disease and the possible beneficial effects of immunosuppresive drugs in better prognosis compared with the same entity in native kidneys.

Acute Kidney Injury↗

[Recurrence and spontaneous remission of nephrotic syndrome in secondary renal amyloidosis].

Secondary systemic amyloidosis (AA) occurs in association with chronic inflammatory disorders and chronic infections. Regression can occur after therapeutically induced remission of the underlying disease; spontaneous remissions has been reported infrequently. We report a 61 year-old woman, with antecedent pulmonary tuberculosis, who developed a nephrotic syndrome at the time of a respiratory infection. Renal biopsy showed secondary amyloidosis. Remission in the nephrotic syndrome appeared spontaneous, but it recurred in the course of pneumonia, and had a second spontaneous remission a maintained at present.

Amyloidosis↗

[Surgical management of anterior communicating artery aneurysms based on computed tomographic angiography with three-dimensional reconstruction and without preoperative angiography].

OBJECTIVE: To demonstrate the usefulness of threedimensional computed tomographic angiography (CT- 3D-angiography) in the microsurgical management of aneurysms of the anterior communicating artery (AComA). MATERIALS AND METHODS: A total of 28 consecutive patients with ruptured aneurysms of the AComA diagnosed by means of CT-3D-angiography and without preoperative angiography were operated on. The findings of the CT-3D-angiography, microsurgical exploration and clínical data were evaluated. RESULTS: There were no false positive findings nor false negative findings in the diagnosis of the AComA aneurysms. The global sensibility of the examination was 87.9%. The CT-3D-angiography study shows a left A1 segment dominance in 53.6% of cases, a right A1 dominance in 14.3% of cases and both A1 segments of the same diameter in 32.1%. Aneurysms growing on the traject of the AComA were associated with both A1 segments of the similar diameter and an AComA traject pararell to the transverse plane. Aneurysms implanted on the A1-A2 junction were associated with a dominant homolateral A1 segment and an oblique AComA traject. Microsurgical management of the lesions was done a mean of 3.7 days after bleeding. CONCLUSION: The study of patients with acute subarachnoid hemorrhage with CT-3D-angiography allows a reliable diagnosis of AComA aneurysms. The examination gives some anatomical data that allow the study of the hemodinamic changes involved in the development of the aneurysms. Moreover, provides usefull information for the microsurgical clipping. CT-3D-angiography allows to improve some health indicators but its impact in the final result of the patients needs more clinical data.

Adult↗

Characterization of binary solvent mixtures of DMSO with water and other cosolvents.

Binary mixtures of DMSO with nine different cosolvents were characterized in light of the pure solvent scales, using suitable probe/homomorph couples. Various physical (vapor pressure, surface tension, viscosity, and enthalpy of mixing) and spectroscopic (IR and NMR) properties of the DMSO/water mixtures are described in terms of their polarity, acidity, and basicity, and the descriptions are examined with a view to establishing their potential physical significance.

Chemical Phenomena↗

Modulation of the susceptibility of human erythrocytes to snake venom myotoxic phospholipases A(2): role of negatively charged phospholipids as potential membrane binding sites.

Cerrophidion (Bothrops) godmani myotoxins I (CGMT-I) and II (CGMT-II), Asp-49 and Lys-49 phospholipases A(2) (PLA2s), which drastically differ in enzymatic activity, were devoid of direct hemolytic effects on erythrocytes (RBC) from different species despite the fact that enzymatically active CGMT-I was able to hydrolyze RBC membrane phospholipids and disrupt liposomes prepared from RBC lipids. Human RBC did not become susceptible to the toxins after treatment with neuraminidase or after altering membrane fluidity with cholesterol or sublytic concentrations of detergent. Unlike normal RBC, significant hemolysis was induced by CGMT-II and another similar Lys-49 isoform, B. asper MT-II (BAMT-II), in RBC enriched with phosphatidylserine (PS). Hemolysis was greater in RBC preincubated with pyridyldithioethylamine (PDA), a potent inhibitor of aminophospholipid transport. RBC enriched with phosphatidic acid (PA) also became susceptible to the myotoxins but was unaffected by PDA. Cells enriched with phosphatidylcholine (PC) remained resistant to the action of the toxins. BAMT-II also induced damage in black lipid membranes prepared with PS but not PC alone. When RBC binding of BAMT-II was measured by enzyme-linked immunosorbent assay, it was observed that PS- and PA-enriched erythrocytes were always able to capture more toxin than normal and PC-enriched RBC. This effect was significantly improved by PDA (in the case of PS) and it was observed either in the presence or in the absence of calcium in the medium. These data suggest that negatively charged lipids in the outer leaflet of cell membranes constitute myotoxic PLA2 binding sites. The scarcity of anionic phospholipids in the outer leaflet of RBC could explain their resistance to the action of these PLA2s.

Animals↗

Pancreatic panniculitis in a kidney transplant recipient.

BACKGROUND: Pancreatic panniculitis is a rare complication of pancreatic disease. Histopathologic findings are pathognomonic and may be helpful for early diagnosis. METHODS: We present a female kidney transplant recipient, with systemic lupus erythematosus on immunossuppresive therapy, who developed panniculitis. RESULTS: Histological features strongly suggested pancreatic panniculitis and this was confirmed by clinical, laboratory and image findings. CONCLUSION: The characteristic histologic features of pancreatic panniculitis may help to uncover undiagnosed pancreatic disease. Early therapy may avoid ensuing serious complications.

Adult↗

Chitotriosidase genotype and serum activity in subjects with combined hyperlipidemia: effect of the lipid-lowering agents, atorvastatin and bezafibrate.

Chitotriosidase, an enzyme involved in the degradation of chitin-containing pathogens with unclear function in humans, has been proposed as a marker of lipid accumulation in macrophages in different lipid-storage diseases, including atherosclerosis. To evaluate (1) if lipid-lowering treatment could modify serum chitotriosidase activity and (2) be useful in monitoring lipid-lowering treatment, we have analyzed this enzyme activity in the participants in the Atozvastatin Versus Bezafibrate in Mixed Hyperlipidemia (ATOMIX) study, a double-blind, comparative, and randomized study comparing the efficacy of atorvastatin and bezafibrate in mixed hyperlipidemia. Because a common genetic deficiency of chitotriosidase modifies serum quitotriosidase activity, this genetic variation was also studied. Seven subjects of 116 (6.03%) were homozygous, and 46 (39.6%) were heterozygous for the defective allele. Mean serum quitotriosidase activity correlated with allele dosage, as it was found to be of 0, 59.8 +/- 52.6 and 81.2 +/- 41.6 nmol/mL/h, in homozygotes for the defective allele, heterozygotes, and homozygotes for the wild-type allele, respectively (P =.0011 for the difference between the last 2 groups). However, this enzyme activity was not found to correlate with lipid levels before and after treatment with either atorvastatin or bezafibrate, and neither with the intensity of the lipid lowering. These results do not support the use of serum chitotriosidase activity as a biologic marker of atherosclerotic plaque modification related to hypolipidemic treatment.

Adolescent↗

Group B Streptococcal sacroiliitis: case report and review.

Streptococcus agalactiae, or group B Streptococcus (GBS), is the major cause of neonatal meningitis and sepsis but is an uncommon infection in adults. GBS arthritis is rare, and axial involvement with sacroiliitis is even more uncommon. Microbiological diagnosis frequently relies upon positive blood cultures as synovial fluid cultures are usually negative. Severe joint damage may result due to delay in the initiation of antibiotic treatment.

Adult↗

Atorvastatin prevents glomerulosclerosis and renal endothelial dysfunction in hypercholesterolaemic rabbits.

BACKGROUND: Numerous studies have shown that elevated plasma cholesterol can exacerbate renal disease. However, the effect of lipids on renal structure and vascular function in normal kidneys is less well established. Therefore, the aim of this study was to evaluate the impact of hypercholesterolaemia on glomerular structure and vascular reactivity of segmental arteries in rabbits. In addition, we also studied whether or not atorvastatin can prevent these structural and vascular alterations in hypercholesterolaemic rabbits. METHODS: Male New Zealand rabbits were fed either a normal rabbit chow or a diet containing 1% cholesterol and treated or not with atorvastatin (1 mg/kg/day) for 12 weeks. Dose-response curves to acetylcholine (10(-9)-10(-4) mol/l) and sodium nitroprusside (10(-9)-10(-4) mol/l) were studied in segmental arteries in the presence or absence of the thromboxane A2/PGH2 receptor antagonist ifetroban (10(-5) mol/l). Glomerular size and structure were also evaluated. RESULTS: Compared with control animals, hypercholesterolaemic rabbits presented glomerular hypertrophy and several types of injuries (capillary collapse, hyalinosis and alterations of Bowman's capsule), suggesting diffuse glomerulosclerosis. Segmental arteries also showed relaxing responses to acetylcholine and sodium nitroprusside which were lower than and similar to, respectively, those of control animals. The presence of ifetroban improved the acetylcholine response only in hypercholesterolaemic rabbits. Atorvastatin treatment prevented vascular and most glomerular changes associated with hypercholesterolaemia even in the presence of very high cholesterol levels. CONCLUSIONS: Atorvastatin exerts a protective effect on renal damage associated with hypercholesterolaemia even in the presence of deleterious levels of plasma cholesterol.

Acetylcholine↗

Validation of the preparation of individual doses of (131)I-sodium o-iodohippurate ((131)I-hippuran).

The preparation of low activity doses of (131)I-hippuran has a drawback due to its high radioactivity concentration. In this study we diluted the radiopharmaceutical with saline or phosphate buffered saline (PBS) in order to decrease the radioactivity concentration, facilitate the preparation of individual doses and validate these procedures. We prepared doses of approx. 1.85 MBq of (131)I-hippuran from 10 different batches the day before the calibration date: undiluted, and diluted 1:9 with saline or PBS. The radiochemical purity (RCP) was evaluated the day after the expiration date. The percentage of (131)I-hippuran retained on syringes was assessed in vitro, after emptying the syringe and washing it twice with water (n=3 x 27); and in vivo, after the endovenous administration of the dose and washing the syringe twice with the patient's blood (n=3 x 75). Sterility was assessed using fluid thyoglicolate medium (n=3 x 15). All RCP values were greater than those required by the European Pharmacopoeia (>96%) except one of the undiluted (131)I-hippuran (95.8%) doses. No statistical difference was observed among them. The mean undiluted (131)I-hippuran retained in vitro was 5.4% (SD=6.5%), statistically greater (P<0.01) than both saline diluted (mean=1.5%, SD=1.1%) and PBS diluted (mean=2.0%, SD=2.4%). The mean undiluted (131)I-hippuran retained in vivo was 6.4% (SD=5.4%), statistically greater (P<10-5) than both saline diluted (mean=3.1%, SD=2.3%) and PBS diluted (mean=3.1%, SD=3.1%). We concluded that: (1) the dilution of (131)I-hippuran with saline or PBS makes both the preparation of individual doses and its administration to the patient easier without decreasing its radiopharmaceutical quality; and (2) using saline or PBS diluted (131)I-hippuran the percentage of radiopharmaceutical retained on the syringes, after use, is minimized.

Humans↗

Application of a complete factorial design for the production of zeaxanthin by Flavobacterium sp.

Utilizing a four-liter fermentor and applying a complete factorial design 2(3), the combined effects of agitation speed, aeration rate, and corn steep liquor concentration on zeaxanthin production by Flavobacterium sp. were studied. Maximum growth and production of total carotenoids and zeaxanthin were obtained at 600 rpm, 2 vvm and 4.6% corn steep liquor. Under these conditions, zeaxanthin represented 86% of the total carotenoids produced. Lower values of the variables studied resulted in lower growth, volumetric production of zeaxanthin and total carotenoids, and favored the formation of other carotenoids such as beta-carotene and canthaxanthin. The positive effects on growth and total carotenoids and zeaxanthin formation were in a large extent due to the interaction of agitation/corn steep liquor. However, aeration also had a positive effect on growth.

Journal Article↗

Pneumonia in patients with severe burns : a classification according to the concept of the carrier state.

OBJECTIVE: To establish baseline values of pneumonia incidence and mortality and to distinguish primary endogenous from secondary endogenous and exogenous pneumonias in a homogeneous patient population with severe burns. DESIGN: Cohort study. SETTING: A six-bed burn ICU. PATIENTS: All patients of > or = 14 years admitted to the ICU between January 1995 and June 1996 with a total body surface area burn of > or = 20%. INTERVENTION: Collection of data on surveillance samples from throat and rectum on admission and twice weekly afterward, and pneumonias during the ICU stay. MEASUREMENTS AND RESULTS: Fifty-six patients fulfilled the criteria of the study. Mean age was 43 +/- 19.8 years; total body surface area burn, 41 +/- 18.2%; the area of full-thickness burn was 24 +/- 17.7%. Forty-one patients required mechanical ventilation. Twenty-seven patients (48%) experienced 37 episodes of pneumonia. Twenty-one pneumonias were of primary endogenous development, ie, caused by potential pathogens carried in the admission flora. There were 14 secondary endogenous and 2 exogenous infections caused by microorganisms acquired on the burn unit. Inhalation injury was identified in 26 patients. The pneumonia rate was two times higher in the subset of patients with inhalation injury compared with the group of patients without inhalation injury (p < 0.001). Overall mortality was 25%. CONCLUSIONS: This study shows that pneumonia in burn patients is mainly an endogenous problem. Interventions that prevent the development of endogenous infections deserve prospective evaluation in patients with severe burns.

Adolescent↗

Serum manganese concentrations in a representative sample of the Canarian population.

Serum manganese (Mn) concentrations of 368 individuals 6-75 yr of age (179 males and 189 females) living in the Canary Islands were determined by graphite furnace atomic absorption spectrometry. The mean manganese concentration was 1.06+/-0.62 microg/L, ranging between 0.19 and 3.33 microg/L. Most of the analyzed samples (63.3% of the samples) fall within the reference interval (0.54-1.76 microg/L) for apparently healthy people. Individuals from Fuerteventura presented with mean Mn concentrations significantly higher than individuals from the rest of the islands. This could be attributed to differences in the Mn content of soil and/or differences in dietary habits of the population. Serum Mn concentration did not vary with gender, and individuals younger than 18 yr old had the highest mean Mn concentration, compared to the rest of the age groups considered. No relation to socioeconomic status, educational level, and tobacco or alcohol consumption was found. However, the serum Mn concentration tended to decrease when increasing the consumption of wine or beer. Sportsmen presented significantly higher serum Mn concentrations than the rest.

Adolescent↗

Effect of bicarbonate/lactate peritoneal dialysis solutions on human mesothelial cell proliferation ex vivo.

Peritoneal membrane suffers structural and functional changes over time on peritoneal dialysis (PD)--in part, owing to the dialysis solutions currently used. Low pH seems to be an important element associated with solution bioincompatibility. Bicarbonate-containing fluids open new perspectives on this issue. The present study compared the effects of bicarbonate/lactate (Bic/Lac) solution (25 mmol/L bicarbonate, 15 mmol/L lactate) and lactate (Lac) solution (40 mmol/L lactate) on mesothelial cell (MC) growth in culture. Eight stable PD patients were asked to collect peritoneal effluent from an 8-hour dwell on two separate days, within an interval shorter than one week. For the first dwell, Lac solution was infused; for the second dwell, Bic/Lac solution was instilled. Human MCs were isolated from the effluent, seeded in 25-cm2 tissue culture flasks, and grown ex vivo. Morphology of the cells was also evaluated. In all effluents, MCs were present in mean amounts of 26,939 +/- 21,267 cells (Bic/Lac) and 25,986 +/- 15,286 cells [Lac, p = nonsignificant (NS)]. Morphology of the MCs was similar with both solutions (87.5% typical). After initial culture, MCs from 6 patients using Bic/Lac (75%) and 3 patients using Lac (37.5%) reached confluence. At this time, the number of MCs from the 3 patients who showed MC growth with both solutions was slightly higher with Bic/Lac-buffered fluid (Lac: 1,154,125 +/- 213,333 cells; Bic/Lac: 1,198,291 +/- 806,713 cells). To summarize: 3 patients showed MC growth under both solutions; 3 patients showed MC growth only under Bic/Lac solution; and 2 patients showed no MC growth at all. After cells were seeded in 24-well plates, the MC growth curve was performed in 4 cases of Bic/Lac solution use and in 3 cases of Lac solution use. Although no significant differences were observed between the solutions, the final number of MCs obtained was higher with Bic/Lac solution use. In conclusion, MCs released into peritoneal effluent under bicarbonate/lactate-buffered peritoneal dialysis solution are associated with a greater ex vivo proliferation capacity than those released under lactate solution in the same patient. This finding may demonstrate better biocompatibility for Bic/Lac solution.

Bicarbonates↗