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Biomedical subjects

L Reyes

Publications and source records attributed to L Reyes.

At least 55 records · Page 3Linked to original sources
PubMed1994

Epidemic optic neuropathy in Cuba. Eye findings.

OBJECTIVE: To characterize and establish a clinical definition of the optic neuropathy that appeared in epidemic form in Cuba in 1992 and 1993. METHODS: At the invitation of the Cuban Ministry of Health, Havana, members of ORBIS International and the Pan American Health Organization, assembled teams that traveled to Cuba in May 1993. We were initially briefed by Cuban national experts in the areas of virology, nutrition, toxicology, ophthalmology, neurology, and public health. We then examined 20 patients on our own. Thirteen of these patients underwent a comprehensive neuro-ophthalmologic examination, including neurologic examination, ophthalmologic examination, visual fields, optic nerve function studies, contrast sensitivity studies, and funduscopy. We returned 4 months later to perform an additional 12 comprehensive neuro-ophthalmologic and follow-up examinations. RESULTS: Only seven of the 13 patients who were alleged to have the optic form of the epidemic and who were rigorously and systematically examined on the first visit demonstrated a bilateral optic neuropathy. These seven patients had several features that included decreased visual acuity, poor color vision, central scotomas, decreased contrast sensitivity, saccadic eye movements, and most prominent and distinctive of all, nerve fiber layer wedge defects of the papillomacular bundle. Our clinical definition was then implemented by the Cuban ophthalmologists and epidemiologists. On returning 4 months later, we found that all newly presented patients were correctly diagnosed to have the epidemic disease. With the new case definition and the application of a few simple psychophysical tests, the false-positive rate of diagnosis became much lower. After vitamin therapy, we reexamined the patients seen on our initial visit, and all showed marked improvement. CONCLUSIONS: The Cuban epidemic was characterized by an optic neuropathy with features that were similar to those of tobacco/alcohol amblyopia and Leber's optic atrophy. Recent political, economic, and social changes in Cuba may have contributed to the nutritional and/or toxic compromise of mitochondrial function of an acquired nature, which led to selective retinal ganglion cell damage. We have termed this condition Cuban epidemic optic neuropathy.

Adult↗
PubMed1994

Determination of Toxoplasma gondii in several organs of cattle by carbon immunoassay (CIA) testing.

Samples of muscle, heart, liver and lung were tested for the presence of Toxoplasma gondii using mice as a biologic detector and the carbon immunoassay (CIA) for immunological diagnosis. In positive tissues the percentage of samples positive ranged from 10 to 50% which indicates the importance of cattle in the epidemiology of Toxoplasma in Costa Rica. We discuss these findings in relation to the transmission of the parasite in Costa Rica.

Animals↗
PubMed1993

The prevalence of hepatitis A, B and C infection among different ethnic groups in Belize.

Little is known about the prevalence of infection with hepatitis viruses in Belize, Central America. We conducted a serologic survey among members of the Belize Defence Force (BDF), which is composed of the five major ethnic groups in Belize, to estimate prevalence rates of hepatitis A, B, and C among military-aged men and women in Belize. Of approximately 600 men and women in the BDF, 492 (82%) completed a questionnaire and blood collection. Antibody to hepatitis A was found in 94%, with similar rates by age, sex, rank, and ethnicity. Antibody to hepatitis B core antigen (anti-HBc) was found in 31%. Rates of anti-HBc varied significantly among the ethnic groups with the lowest rates in Mestizo (5%) and Mayan Indians (9%), and significantly higher rates among Creoles (30%) and Garifuna (56%). Rates increased with increasing age from 28% in those 18-24 years old to 35% in those > or = 35 years old (P = 0.07, by chi-square test for trend). Hepatitis B surface antigen was found in 21 (4%) overall. Antibody to hepatitis C was found in two (0.4%). In this young healthy population, exposure to hepatitis A before the age of 18 is almost universal, while exposure to hepatitis B is related to age and ethnic origin.

Adult↗
PubMed1993

Natural and induced blood dissemination of Toxoplasma gondii: experimental model in white mice and hamsters.

Blood inoculation in mice showed that Toxoplasma organisms circulate in blood after 1 h of oocyst infection. Parasites were detected up to 15 days later and then disappeared from the bloodstream concomitantly with cyst formation in the brain, probably due to antibody presence. Immunosuppression caused by cortisone acetate treatment induced Toxoplasma bloodstream invasion in chronically infected mice and hamsters, causing death in some. Natural dissemination is discussed in relation with congenital toxoplasmosis. Induced immunosuppressive effect is compared with that produced by natural diseases such as Hodgkin, lymphoma, AIDS and others.

Animals↗
PubMed1992

Specificity of the carbon immunoassay (CIA) test for the diagnosis of Toxoplasma infections.

A rapid and low cost procedure, the carbon immunoassay (CIA) test, was evaluated for the diagnosis of Toxoplasma gondii infections. Using a closely related parasite (Besnoitia jellisoni) as antigen, and homologous or heterologous immune sera, it was demonstrated by light and electron microscopy that CIA is a very reliable and specific test. As it is neither expensive nor time-consuming, it can be recommended for general and routine laboratory use.

Animals↗
PubMed1991

Membrane-associated ATPase from Zymomonas mobilis; purification and characterization.

The major ATPase (adenosinetriphosphatase, EC 3.6.1.3) activity present in the membrane of Zymomonas mobilis has been isolated, using a novel combination of multifunctional hydrophobic adsorbents. On subjecting the preparation to gel filtration, activity was lost, but could be restored by reconstituting fractions from the column. Subunit composition of the fractions indicated that the Zymomonas mobilis ATPase is of the F0F1 type, and so is probably involved in proton pumping. The contribution of this ATPase to the overall ATP turnover in the cells has been calculated to be approximately 20% and so it may be partly responsible for the phenomenon of 'uncoupled growth' observed with Zymomonas mobilis.

Adenosine Triphosphatases↗
PubMed1991

Immunoglobulin class- and subclass-specific responses to Mycoplasma pulmonis in sera and secretions of naturally infected Sprague-Dawley female rats.

Mycoplasma pulmonis causes chronic murine respiratory mycoplasmosis and genital disease in rats. Specific immunoglobulin M (IgM), IgA, and IgG and its subclasses present in sera and tracheal and uterine lavage samples from 36 naturally infected Sprague-Dawley female rats were tested for reactivity with M. pulmonis in an enzyme-linked immunosorbent assay. Ten specific-pathogen-free Sprague-Dawley female rats served as the negative controls. Tracheal and uterine lavage samples were cultured quantitatively for M. pulmonis. M. pulmonis was isolated from the trachea (35 of 36) and uterus (17 of 36) of naturally infected rats; all rats were infected in at least one of the two sites cultured. M. pulmonis was not isolated from any control rat. There was a significant difference in levels of specific antibody of all classes except IgG2c between control and naturally infected animals (P less than 0.001 for IgM, IgG, IgG1, and IgG2a; P less than 0.002 for IgG2b; and P less than 0.02 for IgA). There was no correlation between numbers of M. pulmonis cells isolated and the amount or class of antibody measured in serum or tracheal lavage specimens. The predominant antibodies to M. pulmonis found in the sera of naturally infected rats were IgG and IgM. The IgG2a subclass was responsible for the majority of IgG-positive animals. There were no differences between rats which were positive by culture for M. pulmonis in the uterus (U+) and rats which were negative by culture for M. pulmonis in the uterus (U-) with respect to distribution or amount of antibody classes and subclasses in the serum. However, tracheal wash samples from U+ rats had significantly higher (P less than 0.03) levels of specific IgG1 and IgG2a than those from U- rats. Conversely, IgG2a was present in higher levels in pooled uterine lavage specimens from U- rats than in those from U+ rats.

Animals↗
PubMed1991

Lesbians in currently aggressive relationships: how frequently do they report aggressive past relationships?

Findings are reported from a survey examining the frequency with which women in currently aggressive same-sex relationships also report aggressive past relationships involving female partners, male partners, or members of their family of origin. Particular attention is paid to victims who also used aggression and their perceptions of whether their aggressive behavior was self-defensive or mutually aggressive. Results indicate that about one-fourth of participants had been victims of aggression in current relationships, roughly two-thirds had been victimized by a previous male partner, and almost three-fourths had experienced aggression by a previous female partner. Among those reporting having been both victims and users of aggression, about one-fifth had used aggression in their current relationship, almost one-third used aggression with a previous male partner, and nearly two-thirds had used aggression with a previous female partner. A majority of victims who had also used aggression with a previous male partner characterized this use as self-defense, as compared to only 30% of those who had used aggression with a female partner. Instead, aggression in relationships involving a female partner was most frequently described as mutually aggressive in nature.

Adult↗
PubMed1990

Adrenalectomy for adrenal metastasis from lung carcinoma.

In the past 3 years, five patients with lung carcinoma were found to have enlarged adrenal glands without any evidence of distant metastasis. The patients were treated with adrenalectomy. The cases are presented in order to discuss optimal methods of diagnosis and treatment for this condition.

Adrenal Gland Neoplasms↗
PubMed1989

The comparative results of treatment in idiopathic thoracolumbar and lumbar scoliosis using the Harrington, Dwyer, and Zielke instrumentations.

Forty-five patients with idiopathic thoracolumbar or lumbar scoliosis were treated with the Harrington, Dwyer, or Zielke instrumentation and fusion. The Harrington group achieved a 55% correction of the primary curves, while the Dwyer and the Zielke groups achieved 88 and 91%, respectively. Overcorrection of the curves occurred in a total of nine cases in the latter two groups. The Dwyer and Zielke instrumentations enabled better correction of the curves with a shorter fusion. At subsequent follow-up, the 'adding on' phenomenon as a result of the shorter fusion in the Dwyer group was unchanged, while that in the Zielke group became gradually resolved. The Zielke instrumentation appears to be the apparatus of choice for treatment of thoracolumbar and lumbar scoliosis.

Adolescent↗
PubMed1987

Specific and nonspecific mediation of protective immunity to Toxoplasma gondii.

We studied the specificity of protection conferred by Toxoplasma gondii immune lymphocytes and their supernatants on infected hamster kidney cells, using Besnoitia jellisoni immune lymphocytes as a nonspecific control. The intracellular growth of the organisms was measured by [3H]uracil incorporation, and inhibition of multiplication was used as a measurement of immunity. Although the immune lymphocytes restricted principally the multiplication of homologous organisms, partial protection, expressed against the heterologous organism, was found. This was true for either parasite with intact lymphocytes or their supernatants. Exposure of immune lymphocytes to antigen for 18 to 24 h and treatment of kidney cells with supernatant fluids for 18 to 24 h were required for maximal protection. The specific protective mediator in supernatants of immune lymphocytes was characterized by dialysis as having a molecular weight between 3,000 and 12,000 and was found in the 3,000 to 5,000 peak after Sephadex G-50 chromatography. Nonspecific protective activity was greater than 12,000 by dialysis; it chromatographed in the excluded peak, measuring over 43,000, and was destroyed by exposure to pH 2. In vitro production of lymphokines from toxoplasma immune lymphocytes was first detected 7 to 10 days after vaccination of hamsters. At about the same time, hamsters began to resist challenge infection with the pathogenic RH strain of T. gondii and were able to prevent its multiplication in lungs, liver, spleen, and the subcutaneous infection site. The expression of tissue immunity and the production of toxoplasma-immune lymphokines appear to be time-related events.

Animals↗
PubMed1987

Growth inhibition of Trypanosoma cruzi in cultured murine myocardial cells mediated by a specifically induced lymphokine.

An in vitro model for studying the protection of mouse myocardial cells against Trypanosoma cruzi was developed. It was demonstrated that immune mouse lymphocytes stimulated with a specific antigen elicited a mediator which protected myocardial cells from newborn mice against T. cruzi infection. The substance responsible for this activity was sensitive to acid (pH 2) treatment.

Animals↗
PubMed1986

Ceftriaxone in the treatment of bacterial meningitis in children.

A total of 24 pediatric patients with a diagnosis of meningitis, confirmed by positive CFS culture, were enrolled in the study. All patients received ceftriaxone in different doses. No difference in clinical outcome was found between the patients who received ceftriaxone twice a day and the 11 who received the drug as a single daily dose. The latter dosage proves to be preferable. The therapeutic outcome in this series of patients was 22 cured and 2 failures. Bacteriological and pharmacokinetic findings are discussed.

Bacterial Infections↗