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Biomedical subjects

E Ayala

Publications and source records attributed to E Ayala.

At least 19 recordsLinked to original sources
PubMed2006

Two cases of progressive multifocal leukoencephalopathy after allogeneic hematopoietic cell transplantation and a review of the literature.

Progressive multifocal leukoencephalopathy (PML) is a rare subacute demyelinating disorder of the central nervous system (CNS) caused by the DNA JC human polyomavirus. In immunocompromised hosts, PML is caused by reactivation of a latent infection rather than de novo primary exposure. PML in the setting of hematopoietic cell transplantation (HCT) is exceedingly rare. PML should be considered in the differential diagnosis of HCT recipients, autologous or allogeneic, presenting with worsening of neurological symptoms, especially associated with post-transplant neurodegenerative findings. Although DNA polymerase chain reaction (PCR) of the cerebrospinal fluid (CSF) has emerged as a promising tool for detecting JC virus, a negative result does not rule out PML. Brain biopsy remains the most reliable and accurate method for diagnosing JC virus-associated PML. Presently, there is no universally effective antiviral therapy against JC virus and outcome is fatal in the majority of cases. We hereby describe two cases of PML developing after allogeneic HCT and provide a comprehensive review of the literature.

Adult↗
PubMed2006

Valganciclovir is safe and effective as pre-emptive therapy for CMV infection in allogeneic hematopoietic stem cell transplantation.

Despite significant advances in prevention and therapy, cytomegalovirus (CMV) infection continues to be an important cause of morbidity and mortality in the hematopoietic stem cell transplant (HSCT) recipient. The standard drug for pre-emptive therapy is intravenous ganciclovir (GCV). Valganciclovir (VGC), the oral pro-drug of GCV, has excellent bioavailability and is ideal for oral therapy. Since March 2002, VGC was adopted in our center for outpatient pre-emptive therapy in all patients undergoing allogeneic HSCT. Fifty-two allogeneic HSCT recipients were followed weekly via Digene hybrid capture assay. Patients with a positive assay were treated with VGC 900 mg p.o. b.i.d. x 14 days followed by 900 mg p.o. QD until at least 7 days after a negative test. Eighteen patients (14 sib, four MUD) had 30 episodes of CMV DNA detection treated with oral VGC. Median duration of therapy was 21 days (range 10-21 days). The rate of response was 93% (28/30) as confirmed by a negative assay within 14 days. No significant toxicity was encountered. Two patients failed oral VGC. One case of CMV enteritis was diagnosed in a patient with acute GVHD. Pre-emptive therapy of CMV infection with oral VGC is safe and effective in allogeneic HSCT recipients.

Administration, Oral↗
PubMed2001

Solitary fibrous tumor of the thyroid gland: report of seven cases.

Solitary fibrous tumor is a soft tissue neoplasm initially described in the pleura but subsequently reported in a wide variety of locations. The clinical behavior is usually benign, but the existence of aggressive cases has been documented both in the pleura and in extrapleural sites. In this report clinical and pathologic features of seven solitary fibrous tumors of the thyroid gland are presented. Patients' ages ranged from 43 to 64 years (mean 52 years), and tumor sizes varied from 2 to 6 cm. Grossly, the tumors were white-tan and well circumscribed. Microscopically, there was a variegated, wavy, storiform, hemangiopericytic or desmoid-like arrangement of spindle cells. Trapped thyroid follicles within the tumor and peripheral jagged tumor infiltration among follicles were common. There was immunohistochemical reactivity for CD34, CD99, and bcl-2, and ultrastructural analysis of one tumor was consistent with a fibroblastic lineage. The differential diagnosis included other benign and malignant mesenchymal tumors of the thyroid, spindle cell follicular adenoma, Riedel's thyroiditis, the spindle cell, and paucicellular variants of anaplastic carcinoma, papillary thyroid carcinoma with exuberant nodular fasciitis-like stroma, and the spindle epithelial tumor with thymus-like differentiation. The cumulative data of 13 cases (comprised of the seven present cases and the six previously reported) suggest a benign clinical behavior for thyroid SFT.

12E7 Antigen↗
PubMed2001

[Doppler ultrasound in type I diabetes: preliminary results].

PURPOSE: To study the differences of blood flow in type I diabetes patients using a color Doppler ultrasound. MATERIAL AND METHODS: We measured the systolic peak velocity (Vmax), diastolic velocity (Vmin) as well as the resistance index in the central retinal artery (CRA) and in the ophthalmic artery (OA) using a color Doppler ultrasound in 40 diabetic patients. We classified the patients according to the duration of diabetes, which ranged from 1 to 28 years. and whether retinopathy was present. We compared the results against those obtained in the 40 control subjects without vascular pathology. RESULTS: When the results of the two groups were compared, we found that no decrease was observed in the CRA flow rate in diabetics without retinopathy, however there was a significant decrease in flow velocity in patients with initial (p<0.05), moderate (p<0.001) or proliferative retinopathy (p<0.05). The ophthalmic artery presents an increase in the vascular resistance in diabetics with proliferative retinopathy. As the time of diabetes increases, there is a decrease in the blood flow in CRA and an increase in resistance in the OA. CONCLUSIONS: The Doppler ultrasound is a non-invasive technique which allows us to perform a hemodynamic study of the orbital vessels. It is essential to understand the correlation between blood flow velocity and the severity of retinopathy in diabetes patients as it manifests the relationship between the velocity of the blood flow with the severity of the retinopathy and that there is a direct relationship with the evolution of the diabetes and the flood flow velocity.

Adolescent↗
PubMed1999

Conformational stability of adsorbed insulin studied with mass spectrometry and hydrogen exchange.

A new method is described for direct monitoring of the conformational stability of proteins that are physically adsorbed from solution onto a solid substrate. The adsorption-induced conformational changes of insulin are studied using a combination of hydrogen/deuterium (H/D) exchange and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The effect of the surface hydrophobicity on the adsorption-induced conformational changes in the insulin structure is probed by adsorbing insulin on a hydrophilic silica and a hydrophobic methylated silica surface before subjecting the insulin molecules to the isotopic exchange process. The present study describes the experimental procedure of this new application of MALDI. Results show that insulin is more highly and more irreversibly adsorbed to a hydrophobic methylated silica surface than to a hydrophilic silica surface. Hydrogen-exchange experiments clearly demonstrate that the strong interaction of insulin with the hydrophobic surface is accompanied by a strong increase in the H/D-exchange rates and thus in a reduction in the insulin native structural stability. In contrast, H/D-exchange rates of insulin are somewhat reduced upon adsorption on silica from solution.

Adsorption↗
PubMed1994

Cytomegalovirus in upper gastrointestinal ulcers.

Cytomegalovirus (CMV), an important cause of severe infections in immunocompromised patients, can cause ulcerations anywhere in the gastrointestinal tract, most commonly stomach and colon. Only a few cases of CMV inclusions in gastrointestinal ulcers have been reported in normal hosts. We undertook a prospective study of the incidence of CMV in gastroduodenal ulcerations in immunocompetent patients. Thirty-eight patients who were referred for evaluation of dyspepsia, hematemesis, melena, guaiac-positive stools, or iron deficiency anemia and who had gastric or duodenal ulcerations without stigmata of recent hemorrhage or visible vessel were enrolled in the study. Six biopsies obtained from the ulcer base and margin were submitted for histologic examination, shell-vial viral cultures, and monoclonal antibody testing. Thirty-two patients had gastric ulcer and six had duodenal bulbar ulcer ranging in size from 8 to 20 mm in diameter. Forty-four percent of patients had been taking aspirin or nonsteroidal antiinflammatory drugs (NSAIDs) within 10 days of ulcer discovery. Evaluation of all biopsies in 38 patients failed to document any evidence of CMV by light microscopy, viral cultures, or monoclonal antibody testing. CMV infection is uncommon in the gastrointestinal tract of immunocompetent patients with gastroduodenal ulcers. Even within areas of previous mucosal injury induced by nonsteroidal drugs, no evidence of CMV "superinfection" was found. We conclude that CMV infection is not a significant factor in routine peptic or NSAID-induced ulcer disease, and the discovery of CMV inclusions in gastroduodenal ulcerations should lead to a search for an immunocompromised state.

Adult↗
PubMed1989

Effect of L-lysine monohydrochloride on cutaneous herpes simplex virus in the guinea pig.

The effect of topical applications of crystalline lysine therapy on cutaneous herpes simplex virus (HSV) inoculations and subsequent dorsal root ganglia (DRG) infection was studied in male Hartley guinea pigs. Although HSV-I was recovered from the inoculated sites from all animals, the L-lysine-treated skin remained clinically normal, whereas untreated controls manifested clinical symptoms up to 3 days postinoculation (p.i.). However, cocultivation of DRG (C1-S1) indicated a selective tropism of infective particles to specific DRG in the groups treated with amino acids. In lysine-treated animals, HSV was recovered from a few DRG (T-12, T-13, and L-1) at 3 days p.i. and from DRG T-10 in leucine-treated controls; yet no HSV was recovered from DRG of untreated controls. These results suggest an immunomodulatory effect of L-lysine on inoculation site infections and the possible potentiation of subsequent DRG manifestation in amino-acid-treated animals.

Administration, Topical↗
PubMed1988

Production of pili on Vibrio parahaemolyticus.

Electron microscopic examination showed that all strains of Vibrio parahaemolyticus examined had pili on their surface when the organism was grown on marine agar at 28 degrees C for 6-12 h. The pili were morphologically stable on heat treatment at 60 degrees C for 10 min, but both the lateral and polar flagella possessed by this organism were labile. No immunological cross-reactivity between pili of enterotoxigenic Escherichia coli and Vibrio cholerae non-01 and those of V. parahaemolyticus was observed.

Agglutination Tests↗
PubMed1986

Effects of exposure to high potassium concentration on the longitudinal muscle-myenteric plexus preparation from guinea-pig.

The effect of potassium on the longitudinal muscle-myenteric plexus (LM-MP) preparation from guinea-pig was studied. The strips were exposed to elevated K+ (30 mM, 60 mM, 90 mM, 120 mM or 150 mM). A phasic contraction of the LM-MP was caused by 10 mM K+ or 15 mM K+ followed by an increase of the contractile activity probably due to the increase in acetylcholine release. A higher molarity of K+ produces more marked depolarization in the LM-MP and above 22 mM K+ tetanizing effects were observed. We attempted to demonstrate that opiate-like material could be released when the tissue was exposed to more than 30 mM K+ even though several different neurotransmitters could be liberated by elevated K+ molarities.

Animals↗
PubMed1986

Active and passive immunization with Pseudomonas aeruginosa ribosomal vaccines and antisera in the burned rat model.

Pseudomonas aeruginosa ribosomal vaccines were tested for their ability to protect rats subjected to a 20% total body surface burn against the lethal effects of infection with homologous organisms. When administered prior to burning, the vaccines provided 100% protection. When administered postburning, the vaccine from one strain also provided 100% protection when the time interval between vaccination and infection was 3 days. When this time interval was reduced to 1 or 2 days, approximately 50% protection was obtained with the same vaccine. The vaccine from a second strain tested provided about 50% protection with a 3-day time interval. In addition, passive immunization using antiserum to a ribosomal vaccine was also demonstrated to be effective in protecting burned and infected rats, especially when multiple doses of antiserum were used. In this case, 80% protection was obtained (with no protection observed using multiple doses of normal serum). Finally, a comparison of ribosomal and lipopolysaccharide vaccines and antisera was also performed.

Animals↗
PubMed1977

Effects of pneumococcal infection on rat liver microsomal enzymes and lipogenesis by isolated hepatocytes.

Modification in the enzymatic complement and lipogenic functions of rat liver endoplasmic reticulum (ER) were shown to occur during pneumococcal sepsis. Glucose-6-phosphatase, 5'nucleotidase, esterase, and NADPH cytochrome C reductase decreased in activity by as much as 50% with respect to controls. Hydroxymethylglutaryl-CoA and NADH cytochrome C reductases were increased 6-and 2-fold, respectively. Alkaline phosphatase and inosine-5'-diphosphatase did not differ with respect to fasted controls. The lipogenic capacity of the ER was shown to be enhanced. In vitro [14C]acetate incorporation into cholesterol and other lipids by hepatocytes isolated from infected rats was increased 2-to 10-fold. It is concluded that the flow of acetyl-CoA in liver cell of Streptococcus pneumoniae-infected rats is toward lipogenesis rather than ketogenesis.

Animals↗
PubMed1975

Phagocytosis of Francisella tularensis by Rhesus monkey peripheral leukocytes.

Phagocytosis of Francisella tularensis by rhesus monkey peripheral neutrophils (PMN, was assessed by autoradiography, electron microscopy, and biochemical techniques. PMN, in contrast to mononuclear phagocytes, were unable to phagocytize F. tularensis in vitro in the absence of immune serum. It is postulated that in the nonimmune host the innate inability of PMN to phagocytize F. tularensis deletes one of the possible mechanisms of host defense to bacterial infection and thus permits the early dissemination of F. tularensis to intracellular sites of specific target tissues.

Animals↗
PubMed1975

Aminoisobutyric acid transport in primary cultures of normal adult rat hepatocytes.

In contrast to suspensions of freshly isolated hepatic parenchymal cells (HPC), short-term monolayer cultures of HPC displayed properties of active transport for the amino acid analog aminoisobutyric acid (AIB). The uptake of AIB was inhibited by KCN and iodoacetate, failed to occur at 4 degrees, and was stimulated by glucagon. The apparent Km for AIB uptake by cultured HPC was approximately 19 mM. Glucagon did not alter the apparent Km but did increase V.

Aminoisobutyric Acids↗