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Biomedical subjects

M Alvarez

Publications and source records attributed to M Alvarez.

At least 253 records · Page 14Linked to original sources
PubMed1995

[The physicochemical characterization of the strains isolated during the outbreak of epidemic neuropathy in Cuba. II].

The presence of 2 agents such as a Cox A9 strain and another mild cytopathogenic effect-producing strain, both isolated from patients presenting with epidemic neuropathy is reported in this paper. A mild cutopathogenic effect which was propagated in successive dilutions was developed in the dilution 10(-4) by means of the neutralization test of a Coxsackie A9 virus with its homologous hyperimmune serum. A gradient in saccharose was performed in a mild cytopathogenic effect-producing strain and a typical cytopathogenic effect of an Enterovirus developed from one of the fractions passed in tissular cultures in the presence phosphonoacetic acid (PAA). The possible pathogenic role of these viruses are discussed.

Animals↗
PubMed1995

[The factors affecting the growth of the agent, producing a mild cytopathic effect, isolated in patients with epidemic neuropathy].

Certain factors influencing upon the growth of the agent producer of mild cytopathogenic effect and isolated from the cerebrospinal fluid of patients presenting with epidemic neuropathy are described in this paper. It was demonstrated that a concentration of NaHCO3 was essential for the occurrence of the cytopathogenic effect. Determined concentrations of MnCl2 allowed for the visualization of the cytopathogenic effect and increased viral yields.

Animals↗
PubMed1994

Congenital nephrosis in low-risk pregnancies.

Congenital nephrosis is an autosomal recessive disorder requiring neonatal renal transplant for survival. The postnatal diagnosis rests upon the electron microscopic evaluation of the epithelial foot processes and basal membrane of the glomeruli. The prenatal diagnosis can be suspected in the presence of a positive family history with an amniotic fluid (AF) alpha-fetoprotein level greater than 5 standard deviations (SD) above the population mean accompanied by a negative AF acetylcholinesterase, absent haemoglobin F, and an unremarkable fetal sonographic examination. We reviewed our series of seven cases of congenital nephrosis fulfilling the above criteria; four cases had negative family histories, and in two cases the diagnosis of congenital nephrosis was further supported by the presence of elevated AF albumin concentrations. We conclude that (1) the prenatal diagnosis of congenital nephrosis is feasible in a low-risk population, and (2) an elevated AF albumin concentration may represent an additional marker for the diagnosis of congenital nephrosis, even though false-negative results have been reported.

Amniotic Fluid↗
PubMed1994

C4 gene polymorphism in primates: evolution, generation, and Chido and Rodgers antigenicity.

Eleven new C4d genomic primate sequences of the fourth complement factor (C4) have been obtained. Seven of them belong to five species not yet explored for this gene: Pan paniscus (pygmy chimpanzee), Cercopithecus aethiops (green monkey), Macaca mulatta (rhesus monkey), Macaca fascicularis (cynomolgus), and Saguinus oedipus (cotton top tamarin). The New World monkeys (tamarins, four individuals) sequenced for C4 have a single C4d sequence only, which shows a B isotypic specificity and a Rodgers 3 (Rg3), Chido 1 (Ch1) antigenicity. Rg3 and Ch1 could thus be the oldest Rg/Ch specificity (at least 50 million years old) and Rg1, Rg2, Ch3, and Ch6 could be more recent human-specific antigens. Mechanisms of C4d polymorphism generation were analyzed by compiling all the presently available sequences. Examples of both point mutations and crossing-over events among C4d primate sequences could be detected. The problem of a possible trans-species inheritance of C4d polymorphism was addressed and two apparently contradicting dendrograms were obtained. One of them, constructed by using both exon and intron sequences, does not support trans-species evolution, but supports the proposed theory of extensive homogenization of the C4 genes occurring within each species, because alleles from each primate species cluster together. Another completely different dendrogram, obtained by using exon sequences only, suggests the existence of trans-species evolution for C4d polymorphism, because alleles belonging to different species cluster together in a way similar to that found for HLA class I or II alleles. However, orangutan sequences group together in both kinds of C4d sequence dendrograms and seem to have arisen from an ancestor different from that of chimpanzee, gorilla and man C4d sequences. Finally, further data have been obtained that support trans-species conservation of A-ness and B-ness and the existence of trans-specifically conserved allelic motifs, both in intronic and exonic sequences.

Amino Acid Sequence↗
PubMed1994

Bronchobiliary fistula secondary to biliary lithiasis. Treatment by endoscopic sphincterotomy.

Bronchobiliary fistula is a rare condition, defined by the presence of a passage between the biliary tract and the bronchial tree. Many conditions can give rise to the development of such a communication. Biliary lithiasis is one of those and is perhaps the one most amenable to endoscopic management. We describe a case of bronchobiliary fistula secondary to the development of choledocholithiasis in a cholecystectomized patient. The clinical suspicion was raised by the presence of bilioptosis (bile-stained sputum), and the diagnosis established by endoscopic retrograde cholangiopancreatography. The patient was submitted to endoscopic sphincterotomy and stone extraction, achieving frank clinical alleviation. This case gives us the chance to review bronchobiliary fistulas secondary to biliary lithiasis, placing particular emphasis on the opportunities of endoscopic management.

Biliary Fistula↗
PubMed1994

Fetal membrane rupture is associated with the presence of insulin-like growth factor-binding protein-1 in vaginal secretions.

OBJECTIVE: Our purpose was to determine whether detection of insulin-like growth factor-binding protein-1 in vaginal secretions could be used in the diagnosis of fetal membrane rupture. STUDY DESIGN: Consenting patients (n = 105) with complaints suspicious of membrane rupture between 24 and 42 weeks of gestation who had no evidence of placenta previa were enrolled in the study. The diagnosis of membrane rupture required at least two of the following findings on vaginal examination: pooling of fluid, positive Nitrazine paper (Bristol-Myers Squibb, Cherry Hill, N.J.) test, or microscopic evidence of ferning. A swab of the posterior vaginal fornix was obtained, placed in sample buffer, and analyzed for insulin-like growth factor-binding protein-1 by immunoassay. Data analysis included chi 2 analysis, Student t test, or Mann-Whitney U test and linear regression and receiver operating characteristic curve analysis. RESULTS: A total of 78 (74.3%) patients met the criteria for membrane rupture. There was a highly significant difference in mean vaginal insulin-like growth factor-binding protein-1 concentrations between patients with and without clinical evidence of membrane rupture (553.6 +/- 731.4 micrograms/L vs 3.0 +/- 7.3 micrograms/L, p = 0.0002). Receiver operating characteristic curve analysis demonstrated that the optimal identification of patients with membrane rupture was achieved with an insulin-like growth factor-binding protein-1 value > 3 micrograms/L (sensitivity 74.4%, 95% confidence interval 64.7% to 84.0%; specificity 92.6%, 95% confidence interval 82.7% to 102.5%; positive predictive value 96.7%, 95% confidence interval 92.1% to 101.2%; negative predictive value 55.6%, 95% confidence interval 41.0% to 70.1%). CONCLUSIONS: The presence of vaginal insulin-like growth factor-binding protein-1 is highly predictive of membrane rupture, identifying 74.4% of affected patients with a very low false-positive rate.

Adult↗
PubMed1994

Prolactin gene expression and changes of prolactin pituitary level during the seasonal acclimatization of the carp.

The effect of seasonal acclimatization on the extent of prolactin (PRL) gene expression and on the content of this was studied in summer- and winter-carp (Cyprinus carpio) hormone pituitary glands. PRL content in the rostral pars distalis (RPD) was evaluated by immunocytochemistry using antibodies against a cross-linked synthetic peptide comprising the sequence of 15 amino acids which conform to the primary structure of carp PRL. To assess the level of PRL gene transcription, a 24-mer synthetic oligonucleotide probe whose sequence included nucleotides 2041-2064 located in exon V of the carp PRL gene, was used. Employing in situ hybridization assays, a high expression of PRL mRNA was observed in the RPD of summer-acclimatized carp. A negligible level of transcription was observed in tissue sections of pituitary glands from winter-acclimatized carp. Concurrently, immunodetection of the PRL-producing cells in the RPD revealed that the pituitary hormone level was significantly higher in the warm season-adapted carp.

Acclimatization↗
PubMed1994

Detection of human papillomavirus by nonradioactive hybridization.

The presence of the human papillomavirus (HPV) DNA sequence in cervical smears of women with cervical intraepithelial neoplasia (CIN) was investigated through dot blot using a nonradioactive method based on the principle of enhanced chemiluminiscence. From 154 samples examined, 59 (38.3%) had HPV-related sequences determined by dot-blot hybridization; among these, 18 samples (11.68%) reacted either to HPV 6/11 or to HPV 16/18 probes, 20 (12.98%) reacted to only HPV 16/18, and 21 (13.63%) reacted exclusively to HPV 6/11. The relative sensitivity of the method was controlled comparing the results of both tests with those obtained by Southern blot in 32 samples. The risk of HPV positivity was increased in women who first had intercourse at an early age and in patients with CIN II or III. Both associations were significant at the 95% confidence interval (CI). An increased risk of HPV positivity was also associated with patient's age at diagnosis, education levels, number of sexual partners, and use of oral contraceptives, but none of these factors were significant at 95% CI. Other risk factors for cervical cancer, such as the number of pregnancies or cigarette smoking, were not found to be associated with HPV infection and indicate that the association of these factors with cervical cancer probably is independent of HPV infection. Even if HPV is the major risk factor for CIN, this also supports a multifactorial model of cervical cancer etiology with an increased risk of HPV infection.

Adult↗
PubMed1994

Use of cervical prostaglandin E2 gel in patients with previous cesarean section.

The aim of this study was to determine whether preinduction cervical ripening with prostaglandin E2 (PgE2) gel in patients with one previous cesarean section may be used with the same safety and efficacy as in patients without a uterine scar. Primiparous patients (n = 94) with one previous cesarean section were retrospectively compared to nulliparous patients (n = 866). Both groups underwent preinduction cervical ripening with 2 mg intracervical PgE2 gel. Logistic regression was performed to control for confounding factors. Our statistical power was 90% for detecting a doubling of the complication rate, from 10 to 20%. There were no significant differences in the duration of ruptured membranes or length of labor between the two groups. No significant differences were detected in the rate or indications for cesarean section, presence of thick meconium, epidural anesthesia use, amnionitis, or maternal and neonatal morbidity. There were no cases of uterine rupture in either group. PgE2 gel may be used with the same safety and efficacy in patients with previous cesarean section as in nulliparas.

Administration, Intravaginal↗
PubMed1994

Susceptibility to insulin-dependent diabetes mellitus and short cytoplasmic ATP-binding domain TAP2*01 alleles.

TAP2 genes are placed within the HLA complex, have limited genetic variability and encode two main groups of peptide transporter proteins, the so-called TAP2*01 alleles, with a short ATP-binding domain, and the TAP2*0201 allele with a long domain. These transporters carry antigenic peptides from cytoplasm across the endoplasmic reticulum membrane to release them into nascent HLA class I molecules, which will then travel towards the plasma membrane. The shorter TAP2*01 alleles are present in 99% of diabetics and 90% of controls; these alleles may add slight, although significant and independent, susceptibility to diabetes, particularly in subjects carrying non-Asp 57 at beta DQ. Moreover, this increased susceptibility is not due to linkage disequilibrium with other HLA markers (i.e.: DR4), which does not exist in our Spanish population.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

Accumulation of glutamate by Salmonella typhimurium in response to osmotic stress.

Salmonella typhimurium accumulates glutamate in response to osmotic stress. Cells in aerobic exponential growth have an intracellular pool of approximately 125 nmol of glutamate mg of protein-1. When cells were grown in minimal medium with 500 mM NaCl, KCl, or sucrose, 290 to 430 nmol of glutamate was found to accumulate. Values were lower when cells were harvested in stationary phase. Cells were grown in conventional medium, harvested, washed, resuspended in the control medium or in medium with osmolytes, and aerated for 1 h. With aeration, glutamate was found to accumulate at levels comparable to those observed in exponential cultures. Antibiotics inhibiting protein synthesis did not affect glutamate accumulation when cells were aerated. Strains with mutations in glutamate synthase (glt) or in glutamate dehydrogenase (gdh) accumulated nearly normal levels of glutamate under these conditions. A double (gdh glt) mutant accumulated much less glutamate (63.9 nmol mg of protein-1), but a 1.9-fold excess accumulated when cells were aerated with osmotic stress. Methionine sulfone, an inhibitor of glutamate synthase, did not prevent accumulation of glutamate in cells aerated with osmotic stress. Glutamate dehydrogenase is thought to have minimum activity when ammonium is limiting. Resuspending cells with limiting ammonium reduced glutamate production but did not eliminate accumulation of excess glutamate when cells were osmotically stressed. Amino oxyacetic acid, an inhibitor of transamination reactions, did not prevent accumulation of excess glutamate.(ABSTRACT TRUNCATED AT 250 WORDS)

Bacterial Proteins↗
PubMed1994

Developmental and service needs of school-age children with human immunodeficiency virus infection: a descriptive study.

OBJECTIVE: To describe the developmental functioning and service needs of a group of school-age children with human immunodeficiency virus (HIV) infection. DESIGN: Retrospective data were collected through chart reviews and follow-up telephone calls to primary care givers. SETTING: A multidisciplinary team provided care at a developmental diagnostic and treatment center. PATIENTS: Cases were 90 school-age children (ages 5 to 14 years) with presumed perinatally acquired HIV infection. RESULTS: Forty-four percent of the 86 children on whom there were diagnoses were functioning in the low average to average range of intelligence, whereas 56% were functioning in the borderline range or lower. Fifty percent of the children demonstrated significant language impairments, with 28% also demonstrating an articulation disorder. Thirty-six of the children (42%) were formally diagnosed as having emotional/behavioral disorders. Eighty-six of the children were in school-based programs and of that group, 74% were in special education classes and receiving related services. CONCLUSIONS: Most of the children in this study demonstrated deficits in the cognitive and learning areas, although they are clearly functioning better than earlier studies of children with HIV infection would have predicted. Their service needs include alternative living arrangements, remedial education, and psychotherapeutic interventions. The children's increasing longevity will place strains on the respective service systems.

Adolescent↗
PubMed1994

[Cholestasis caused by Fasciola hepatica].

Human infestation with Fasciola hepatica is observed occasionally. Cholestasis due to parasitic obstruction of the common duct is an infrequent complication. A case of fascioliasis is described in a 56 year-old male with symptoms of biliary colic and biochemical cholestasis. The diagnosis was based on the indirect hemagglutination test and the evidence of Fasciola hepatica in the extrahepatic biliary tract shown by ultrasound and ERCP. The patient presented an acute pancreatic reaction during an attempt at therapeutic endoscopic sphincterotomy. Medical treatment was initiated then with Bithionol. Cholestasis as well as the parasitosis were eliminated. Recovery was demonstrated by the normality of the titres of hemagglutination and of the biliary tract by ERCP.

Cholestasis↗
PubMed1994

[Pseudotumor pancreatic tuberculosis].

A 59 year-old male with a toxic syndrome an a pancreatic pseudotumoral mass. Two pancreatic fine needle aspiration cytologies were negative. Liver and pancreatic surgical biopsies showed a chronic granulomatous tuberculous inflammation. Mycobacterium tuberculosis was isolated in the gastric juice; the urine and sputum cultures was negative. Tuberculostatic treatment with Rifampicin, Isoniazid and Ethambutol was effective. We emphasize the importance of the histological diagnosis in all of pancreatic mass.

Antitubercular Agents↗
PubMed1994

Rhodamine efflux patterns predict P-glycoprotein substrates in the National Cancer Institute drug screen.

Fifty-eight cell lines in the National Cancer Institute drug screen were analyzed for their ability to efflux the fluorescent dye rhodamine 123 as a functional assay for P-glycoprotein (Pgp). Using flow cytometry, the rhodamine fluorescence was measured for each cell line under four incubation conditions, i.e., after accumulation in the presence or absence of the Pgp antagonist cyclosporin A and after efflux in rhodamine-free medium in the presence or absence of cyclosporin A. The results in some cell lines were compatible with Pgp-mediated efflux. There was a significant correlation between mdr-1 expression and rhodamine efflux in the 58 cell lines (r = 0.788, p = 0.0001). Using the rhodamine efflux data as a seed for COMPARE analysis with the cytotoxicity data on > 30,000 compounds in the National Cancer Institute drug screen database, hundreds of compounds with high correlation coefficients were identified. Selected compounds were tested for reversal of cross-resistance in a multidrug-resistant cell line. A high degree of reversibility, up to 10,000-fold, for some of the compounds was noted in the presence of the Pgp antagonist PSC 833. This finding suggested that compounds with predominately Pgp-mediated resistance were being identified. Using these compounds as seeds for COMPARE analysis against a more restricted database of 187 standard agents, a series of standard compounds were repeatedly identified as having high correlation coefficients with the newly identified Pgp substrates. These standard agents, including phyllanthoside, bisantrene, and homoharringtonine, constitute an mdr-1 profile. New agents identified as being highly correlated with these compounds may benefit from clinical trials with Pgp antagonists.

ATP Binding Cassette Transporter, Subfamily B, Mem↗