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Biomedical subjects

M Rodríguez

Publications and source records attributed to M Rodríguez.

At least 235 records · Page 13Linked to original sources
PubMed1996

A novel locus for non-syndromic sensorineural deafness (DFN6) maps to chromosome Xp22.

Non-syndromic X-linked deafness is highly heterogeneous. At least five different clinical forms have been described, but only two loci have been mapped. Here we report a Spanish family affected by a previously undescribed X-linked form of hearing impairment. Deafness is non-syndromic, sensorineural, and progressive. In affected males, the auditory impairment is first detected at school age, affecting mainly the high frequencies. Later it evolves to become severe to profound, involving all frequencies for adulthood. Carrier females manifest a moderate hearing impairment in the high frequencies, with the onset delayed to the fourth decade of life. Deafness was assumed to be X-linked dominant, with incomplete penetrance and variable expressivity in carrier females. The family was genotyped for a set of microsatellite markers evenly spaced at intervals of about 10 cM. We found evidence of linkage to markers in the Xp22 region (maximum lod score of 5.30 at theta = 0.000 for DXS8036 and for DXS8022). The position of the novel deafness locus (DFN6) was refined by haplotype analysis. Mapping of the breakpoints in two critical recombinants allowed us to define an interval for DFN6, delimited by DXS7108 on the distal side and by DXS7105 on the proximal side, and spanning a genetic distance of about 15 cM.

Audiometry, Pure-Tone↗
PubMed1996

Serum angiotensin converting enzyme and C4 protein of complement as a combined diagnostic index in alcoholic liver disease.

Diagnosis of liver cirrhosis relies on hepatic biopsy. So far, attempts have failed to achieve a serologic test that differentiates cirrhosis from other hepatic conditions. The aim of this work was to assess the diagnostic value of the ratio of serum angiotensin converting enzyme activity (SACE) and the levels of protein C4 of serum complement (SACE/C4) in differentiating cirrhotic from noncirrhotic alcoholic liver diseases. In this study, 68 active alcoholic patients (17 with fatty liver or minimal changes, 11 with acute alcoholic hepatitis and 40 with cirrhosis) were included. Twenty healthy subjects were studied as a control group. Liver biopsy was performed in all patients. SACE levels were significantly higher in the group with cirrhosis when compared with the group of patients without cirrhosis and the control. On the other hand, serum C4 level decreased as liver damage progressed. SACE values above 25 IU/l had a sensitivity of 92.5 percent (95 percent confidence interval, 87.5 to 97.5) and a specificity of 79 percent (95% percent confidence interval, 70.5 to 87.5), in detecting those patients with liver cirrhosis. The sensitivity further increased to 95 percent (95 percent confidence interval, 90.5 to 99.5) and the specificity to 100 percent when the SACE/C4 ratio was used and a cutoff point of 145 was chosen. To conclude, in alcoholics SACE is specifically elevated in patients with cirrhosis, and the SACE/C4 ratio is a excellent biochemical index for the diagnosis of cirrhosis in alcoholic patients.

Adult↗
PubMed1996

Gram-positive, catalase-positive cocci from dry cured Iberian ham and their enterotoxigenic potential.

Iberian ham is an uncooked, cured meat product ripened under natural uncontrolled conditions for 18 to 24 months. Gram-positive, catalase-positive cocci are the main microbial population in Iberian ham for most of the ripening time. Since some of these organisms are able to produce enterotoxins, adequate characterization and toxicological study are needed. For this, 1,327 gram-positive, catalase-positive cocci, isolated from Iberian hams at different stages and locations, were characterized by physiological and biochemical tests. Selected isolates were further characterized by guanine-cytosine (G+C) content and restriction enzyme analysis of genes coding for 16S rRNA. The toxigenic potential of these organisms was tested with specific DNA gene probes for staphylococcal enterotoxins A, B, C, and D and confirmed by semiquantitative sandwich enzyme immunoassay. The majority of the isolates were identified as Staphylococcus spp. and Micrococcus spp. Non-identified gram-positive, catalase-positive cocci which were moderately halophilic and showed a 42 to 52% G+C content were detected. A great variety of staphylococcal strains were found within the different species at any sampling time. Two strains of Staphylococcus xylosus, one Staphylococcus cohnii strain, and four of the non-identified organisms with 42 to 52% G+C contents hybridized with some of the DNA probes for C and D staphylococcal enterotoxin genes. S. xylosus hybridizing with C-enterotoxin probe reacted with both C and D enterotoxins in the immunological test. In addition, enterotoxin D was confirmed in the nonidentified strains. Some toxigenic organisms were isolated from the final product, posing a health hazard for the consumer.

Animals↗
PubMed1996

Colonoscopic findings in patients with lower gastrointestinal bleeding send to a hospital for their study. Value of clinical data in predicting normal or pathological findings.

BACKGROUND: Lower gastrointestinal bleeding is a highly frequent clinical problem that may reflect serious pathology in the colon. Colonoscopy is generally accepted as the diagnostic procedure of choice. Decisions as to whether to carry out colonoscopy or not, are not well defined. METHODS: 536 colonoscopies, made to discover the cause of lower gastrointestinal bleeding were analyzed and a final 457 included in the study. All of these patients came to the hospital because they had presented at least in one occasion, one episode of rectal bleeding, and were send by the specialist of the zone, in order to achieve a correct diagnosis of its process. In all cases the following associated symptoms were analyzed: the presence of diarrhea, constipation, abdominal pain and rectal mass on examination. The characteristics of lower gastrointestinal bleeding were analyzed in a subset of 150 consecutive patients. RESULTS: Mean age was 59 +/- 16.9 years. 54.5% were male and 45.5% female. The exploration was normal until the cecum in 146 patients (32%). In the remaining 311, the findings were: polyps (25.1%), diverticular disease (24%), neoplasia (12.6%), inflammatory bowel disease (9.4%), unspecific proctitis (2.4%), ischemic colitis (2.4%), angiodysplasia (1.9%), infectious colitis (1.1%), and miscellaneous (0.7%). An age of less than 40 years and the existence of anal pathology were significantly more frequent among patients with a normal examination (p < 0.001), but with a sensitivity of only 66%. No differences were found among patients with disordered bowel frequency or abdominal pain in relation to the colonoscopic findings. Previous presence of a rectal mass when the examination proved abnormal (p=0.06). Intermittent bleeding and the presence of blood in the stools were more frequent in patients with normal examination (p= 0.07 and p< 0.05, respectively). No significant differences in relation to colour, duration of bleeding, or to whether toilet paper was stained with blood were found. CONCLUSIONS: 1) The more frequent endoscopic findings were polyps and diverticular disease. 2) Clinical data are of little value in predicting a normal examination. 3) Total colonoscopy appears to be the first procedure of choice in all patients with lower gastrointestinal bleeding, irrespective of the clinical data and the presence of anal pathology.

Adolescent↗
PubMed1996

[Evoked potentials and psychometric tests in the diagnosis of subclinical neurological damage in a group of workers exposed to low concentrations of mercury vapor].

We study the effects of low concentrations of mercury vapour on the nervous system of a group of eleven workers of a chloroalkali plant exposed to it. Twenty-three non-exposed workers in the same factory were used as control group. We used clinical and analytic explorations, psychometric tests and evoked potentials to evaluate the subjects. The average Hg in urine of the exposed group was 41.74 micrograms/gr creatinine and the average of the non-exposed group as 9.71 mu/yr. In the exposed group the evoked potentials have found a slowing-down of conduction in all the nervous paths studied (optical, auditive and somatosensory) and in the latency of P300 wave, although this was not statistically significant compared to the control group. Of the psychometric test used, only Rey's Complex Figure Test showed deterioration in the visual memory subtest of the exposed group (p < 0.05) compared to the control group, although in Wechsler's digit span test lower scores were obtained which were close to being statistically significant comparing the averages of the two groups (0.05 < p < 0.051). Bearing in mind these results we think that the amounts of Hg in urine and TLV-TWA (50 micrograms/gr creatinine and 50 micrograms/m3 respectively) accepted by most authors as innocuous should be reduced.

Adult↗
PubMed1996

Biochemical characterization of the recombinant Boophilus microplus Bm86 antigen expressed by transformed Pichia pastoris cells.

In the present paper we report the biochemical characteristics of the recombinant tick (Boophilus microplus) gut antigen Bm86 that previously has been cloned, expressed and recovered at high levels in the methylotrophic yeast Pichia pastoris. The results demonstrate that rBm86 had a modification at position 92 (Thr replaced by Ile) and aggregated, forming particles ranging between 17 and 40 nm. The rBm86 was N-glycosylated, having at least two non-glycosylated sequons (Asn-329 and Asn-363) and a ratio of only 0.4/65 (free Cys/total Cys)/mol of protein.

Amino Acid Sequence↗
PubMed1996

Recombinant Acremonium chrysogenum strains for the industrial production of cephalosporin.

Conventional strain improvement programs based on random mutagenesis and rational screening have meant valuable results to the antibiotic producing companies. The development of recombinant DNA techniques and their applications to the industrially-used cephalosporin-producing fungus Acremonium chrysogenum has provided a new tool, complementary to classical mutation, promoting the design of alternative biosynthetic pathways making it possible to obtain new antibiotics and to improve cephalosporin production. Yield increases have been achieved by increasing the dosage of the biosynthetic genes cefEF (deacetoxycephalosporin C expandase/hydroxylase) and cefG (deacetylcephalosporin C acetyltransferase) or enhancing the oxygen uptake by expressing a bacterial oxygen-binding heme protein (Vitreoscilla hemoglobin). New biosynthetic capacities such as the production of 7-aminocephalosporanic acid (7-ACA) or penicillin G have been achieved through the expression of the foreign genes dao (D-amino acid oxidase) coupled with cephalosporin acylase or penDE(acyl-CoA:6-APA acyltransferase) respectively. Confined manipulation of the above-mentioned recombinant strains must be performed according to standing rules.

Acetyltransferases↗
PubMed1996

A reduced PTH response to hypocalcemia after a short period of hypercalcemia: a study in dogs.

The relationship between PTH and calcium is best represented as a sigmoidal curve. In the normal animal and human, basal PTH is positioned at approximately 25% of maximal PTH and responds rapidly to small changes in calcium in either direction. Since PTH secretion is designed to respond to either hypo- or hypercalcemia, the study was performed to evaluate whether the parathyroid gland would respond differently to hypocalcemia when the reduction in serum calcium was initiated from sustained hypercalcemia with maximal PTH suppression. Nine dogs were studied and the experimental protocol consisted of two separate parts in which the same dogs were used and the order of study was randomly assigned. For the hypercalcemic part, calcium chloride was infused intravenously to increase serum calcium to between 1.60 and 1.70 mM at 30 minutes and then continued for another 90 minutes to clamp the serum calcium at this level. Sodium EDTA was then infused to lower the serum calcium at a constant rate to less than 0.85 mM. For the normocalcemic part, 5% dextrose in water was infused for two hours to control for fluid volume and time, and then EDTA was infused to lower the serum calcium at a constant rate to less than 0.85 mM. The results show that for the same serum calcium concentration at every 0.05 mM decrement in serum calcium below normal, PTH was less in the hypercalcemic than the normocalcemic dogs (P < 0.02). During the induction of hypocalcemia in the normocalcemic dogs, a characteristic sigmoidal curve was observed in which a small decrease in the serum calcium induced a brisk increase in PTH and a maximal PTH level was rapidly attained; however, during the induction of hypocalcemia in the hypercalcemic dogs, the increase in PTH was progressive, but linear and it was not certain that a maximal PTH level was attained. In conclusion, a sustained period of hypercalcemia resulted in a decreased PTH response to hypocalcemia and reduced the efficiency of the sigmoidal PTH-calcium relationship. Whether the mechanism for this difference in PTH secretion is due to secretory products, modification of the calcium receptor, or changes in intercellular communication among parathyroid cells deserves further study.

Animals↗
PubMed1996

Seroepidemiology of measles, mumps and rubella virus infections in normal children and adults in southern Granada, Spain: response to a vaccination programme.

A seroepidemiological study of measles, mumps and rubella virus infection in normal children and adults in southern Granada, Spain, and the response to a vaccination programme was carried out. Protection from the mumps and rubella virus was reduced in the group of 3 to 7 year-old children vaccinated at age 15 months indicating the need for revaccination against rubella as well as the mumps virus.

Adult↗
PubMed1996

Dentin bond strength of fluoride-releasing materials.

PURPOSE: To evaluate the shear bond strength to dentin of fluoride-releasing materials. MATERIALS AND METHODS: Human, noncarious extracted permanent molars stored in distilled water were used. Flat buccal and lingual dentin surfaces were ground wet on 600-grit silicon carbide paper. The teeth were then distributed at random into three groups of 8 teeth (16 surfaces) each: Group 1: Compoglass; Group 2: Fuji II LC; Group 3: Dyract. Cylindrical samples of the materials were prepared in plastic molds and bonded to the dentin surface according to the manufacturers' instructions. All samples were placed in distilled water for 24 hours, thermocycled for 500 cycles in distilled water at 6 degrees C and 60 degrees C and sheared with an Instron at a crosshead speed of 0.5 mm/minute. RESULTS: In MPa: Group 1: 16.29 +/- 5.35; Group 2: 15.42 +/- 4.77; Group 3: 15.33 +/- 6.96. ANOVA revealed that there was no statistically significant difference between the groups. Fracture patterns, examined with the SEM, revealed material cohesive failures for all groups.

Analysis of Variance↗
PubMed1995

[The perception of improvement in asthma].

BACKGROUND: The capacity of stable asthma patients to recognize the presence of air flow obstruction, treatment improvement and daily variations was studied. METHODS: Placebo and 500 micrograms of inhaled terbutaline for two consecutive days were administered to 39 patients. The subjective impressions were compared with spirometric results. RESULTS: Thirty patients presented obstruction of which 7 reported to be asymptomatic and 9 presented normal spirometry of which 3 reported to be symptomatic. Fifty-four percent (21) did not correctly recognize whether they improved with the medication either of the two days. Eleven patients reported improvement with placebo without significant spirometric changes. Eighteen preferred terbutaline and 5 the placebo while 16 were indifferent out of whom 7 (43%) had improved with only the bronchodilator. The FEV1 difference between the two days was > 10% in 18 patients of which this was not perceived in 10. CONCLUSIONS: Objective controls are necessary for the evaluation and follow up of patients with stable asthma.

Adolescent↗
PubMed1995

A sandwich ELISA based on anti-apo(a) and anti-apo B monoclonal antibodies for lipoprotein(a) measurement.

Lipoprotein(a) (Lp(a)) is one of the most important independent risk factors for the prediction of premature atherosclerosis. Lp(a) is a low-density lipoprotein (LDL)-like particle which contains a glycoprotein (apoprotein(a)) disulfide linked to apo B-100. We describe a sandwich ELISA based on an anti-apo(a) monoclonal antibody (MAb) and an anti-apo B MAb for the quantitative determination of Lp(a) in human serum. The assay is sensitive, precise and specific. Samples with different apo(a) isoforms had a linear response in a range of 3-70 mg/dl of Lp(a). Correlations between the ELISA and a commercial ELISA, an immunoradiometric assay and electroimmunodiffusion were 0.92, 0.96 and 0.98, respectively. The frequency distribution of Lp(a) concentration in blood donors showed the skew toward the right reported in other populations. Patients with angiographically assessed coronary atherosclerosis had three times higher levels of Lp(a) than those with no signs of coronary atherosclerosis.

Animals↗
PubMed1995

Light-induced arousal affects simultaneously EEG and heart rate variability in the rat.

In awaken rats, ECG and EEG were simultaneously analysed in order to quantify the cortical EEG and beat-to-beat heart rate variability (HRV) in response to light onset. The HRV bands LF (40-200 mHz), MF (200-600 mHz) and HF (600-2500 mHz) and the EEG bands delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz) and beta (13-32 Hz) were assessed. Light onset induced a significant arousal reaction in the EEG, manifested by a global decrease in total spectral power and a shift towards theta and beta bands, while total HRV spectral power increased, with a shift to the sympathetic-related MF band. This simultaneous changes in HRV and EEG induced by light onset could be triggered by the same common factor that controls both oscillatory responses.

Animals↗
PubMed1995

Repeated intracerebroventricular administration of taurine lowers LH levels and postpones vaginal opening in peripubertal female rats.

UNLABELLED: We investigated the effect of repeated intracerebroventricular injections of taurine (Tau, 0.15 mumol/3 microliters distilled water), administered during postnatal days 23-29, on serum LH levels, and on the hypothalamic content of LHRH and amino acid neurotransmitters (measured by HPLC and electrochemical detection) in 30-day-old female rats (n = 18). Treatment with Tau lowered serum LH (Tau: 0.20 +/- 0.04; CONTROLS: 1.04 +/- 0.21 ng/ml RP3; mean +/- S.E.M.; P < 0.05) as well as hypothalamic LHRH levels (Tau: 82.6 +/- 9.5; controls: 128.7 +/- 14.1 pg/mg wet tissue, P < 0.05). Tau treatment doubled hypothalamic GABA levels (Tau: 31.3 +/- 2.9; CONTROLS: 15.6 +/- 1.2 nmoles/mg wet tissue, P < 0.001). In a second group of animals (n = 13), Tau treatment delayed vaginal opening by more than 2 days (P < 0.05 vs. controls). It is concluded that supplementation with Tau during the fourth postnatal week reduces LHRH/LH secretion and postpones sexual development, perhaps by increasing the activity of the hypothalamic GABAergic system.

Amino Acids↗