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Biomedical subjects

E A Gomez

Publications and source records attributed to E A Gomez.

At least 19 recordsLinked to original sources
PubMed2006

Morphometric changes in goat sperm heads induced by cryopreservation.

Two experiments were designed to evaluate the effect of cryopreservation on morphometric characteristics of the goat sperm head. To address this question, we evaluated the size of the sperm head in fresh control cells, post-cooling cells after equilibration with the glycerol preservation solution, and post-thawing cells. Assessment was by automated morphometric sperm head analysis (ASMA) using phase-contrast microscopy without staining. In the first experiment, ASMA was performed on heterospermic pooled samples (fresh, post-cooling after equilibration with the glycerol preservation solution and post-thawing): length, width, area and perimeter were measured. In the second experiment, sperm viability was assessed by Hoechst staining and head morphometry was carried out as before, simultaneously during the cryopreservation process, and the head size was identified for both live and dead spermatozoa. The data were analysed by principal component analysis (PCA). The purpose of PCA is to derive a small number of linear combinations (principal components) from a set of variables (length, width, area and perimeter), that retain as much of the information in the original variables as possible. The main findings that have emerged from this study are that (i) a simple procedure has been developed for measuring spermatozoa heads without staining, which minimises the possibility that sperm head dimensions were influenced by procedural artefacts; (ii) the dimensions of goat sperm heads after cryopreservation in skimmed milk-glucose medium were smaller than in fresh sperm, but this was due to the equilibration phase with the cryoprotectant and not to the cryopreservation process itself; and (iii) dead spermatozoa showed smaller heads than live sperm, consequent upon the loss of membrane function. No differences were observed between post-cooling cells after equilibration with the glycerol preservation solution and post-thawing spermatozoa and only minor osmotic differences between them and fresh sperm were observed.

Animals↗
PubMed2004

Elliptical selection experiment for the estimation of genetic parameters of the growth rate and feed conversion ratio in rabbits.

Two elliptical selection experiments were performed in two contemporary sire lines of rabbits (C and R) in order to optimize the experimental design for estimating the genetic parameters of the growth rate (GR) and feed conversion ratio (FCR). Twelve males and 19 females from line C, and 13 males and 23 females from line R, were selected from an ellipse defined by a quadratic index based on these traits. Data from 160 rabbits of each of the parental generations of lines C and R and their offspring (275 and 266 animals, respectively) were used for the analysis. A Bayesian framework was adopted for inference. Marginal posterior distributions of the genetic parameters were obtained by Gibbs sampling. An animal model including batch, parity order, litter size, and common environmental litter effects was assumed. Posterior means (posterior standard deviations) for heritabilities of GR and FCR were estimated to be 0.31 (0.10) and 0.31 (0.10), respectively, in line C and 0.21 (0.08) and 0.25 (0.12) in line R. Posterior means of the proportion of the variance due to common litter environmental effects were 0.14 (0.06) and 0.21 (0.06) for GR and FCR, respectively, in line C and 0.17 (0.06) and 0.22 (0.06) in line R. Posterior means of genetic correlation between both traits were -0.49 (0.25) in line C and -0.47 (0.32) in line R, indicating that selection for GR was expected to result in a similar correlated response in FCR in both lines.

Animal Feed↗
PubMed2003

Randomised efficacy and safety study of two 3-day artesunate rectal capsule/mefloquine regimens versus artesunate alone for uncomplicated malaria in Ecuadorian children.

The combination of artesunate and mefloquine is one of the most effective treatments against multidrug-resistant falciparum malaria. Experience in children is however limited. The objective of this study was to compare the efficacy and safety of two artesunate/mefloquine combinations with artesunate monotherapy in Ecuadorian children. A total of 150 children with an age between 2 and 12 years, confirmed to have uncomplicated falciparum malaria, were randomly selected and divided in three treatment groups of 50 patients each. Group 1 received 50 mg rectal capsules alone (40 mg/kg total dose) administered over 6 days. Group 2 received 50 mg rectal capsules (30 mg/kg total dose) for 3 days combined with mefloquine (20 mg/kg total dose) on day 1. Group 3 was treated with 50 mg rectal capsules (30 mg/kg total dose) for 3 days, combined with mefloquine on days 1 and 3 (15-17 mg/kg total dose). Patients were continuously followed up and controlled by clinical and laboratory examinations for 7 days as well as on days 14, 21 and 28. An additional parasite examination was performed at 2 months following therapy. Clearance of parasitaemia was comparable between treatment groups. These were 9.2, 9.2 and 8.3 h for Groups 1, 2 and 3, respectively. Cure rates at day 28 were 76, 96 and 94% and after 2 months 60, 88 and 80%, respectively. There were no adverse events (AEs) reported during the study. Vital signs and laboratory examinations revealed no changes of clinical relevance. It can be concluded that the combination of artesunate rectal capsules with mefloquine is effective and safe. Starting concomitant administration already on day 1 is well tolerated. This combination significantly reduces the incidence of recrudescence compared to artesunate monotherapy. Comparing the two tested artesunate/mefloquine regimens, a total mefloquine dose of 20 mg/kg seems to be more effective compared to a total dose of 15-17 mg/kg. Further studies seem to be warranted.

Administration, Rectal↗
PubMed2002

Usefulness of sampling with cotton swab for PCR-diagnosis of cutaneous leishmaniasis in the New World.

In this study, we tested the polymerase chain reaction (PCR)-method to diagnose cutaneous leishmaniasis (CL) by taking exudate materials from lesions with cotton swabs, using our previously tested (PCR) panel comprised of Leishmania (Viannia) panamensis, L. (V.) braziliensis, L. (V.) guyanensis, L. (Leishmania) mexicana and L. (L.) amazonensis. The objectives of the present study were to improve the sampling method convenient for the patients and to test the usefulness of samples taken with cotton swabs. Sixteen patients were clinically diagnosed to have CL including one case of diffuse cutaneous leishmaniasis (DCL) in Ecuador and the causative Leishmania parasites were identified by PCR. All the 12 samples from CL patients of La Mana, positive for Leishmania DNA, were identified as L. (V.) panamensis, while two from CL of Huigra and one from DCL of San Ignacio were L. (L.) mexicana. In the field condition, taking biopsy material is not only painful but sometimes causes iatrogenic bacterial infections. Considering the sensitivity of the test, and convenient sampling procedure, it may be suggested that collection of exudates using cotton swabs may be a better alternative to biopsy sample for PCR-diagnosis of CL.

Adult↗
PubMed2001

Detection of species of the subgenus Leishmania parasites using polymerase chain reaction and southern blotting.

In this study, an attempt was made to identify different Leishmania species by polymerase chain reaction (PCR). Fourteen Leishmania strains from stock were tested by PCR and Southern blotting. A pair of primers were employed that anneal to the kinetoplast DNA sequence conserved among subgenus Leishmania. Of the 14 Leishmania strains used in this study, six showed strong bands of approximately 170 bp, and all the positive strains belonged to the species of the subgenus Leishmania viz., Leishmania (Leishmania) garnhami, L. (L.) amazonensis, L. (L.) pifanoi, L. (L.) mexicana, L. (L.) chagasi, and L. (L.) major All the species belonging to the subgenus Viannia used in this study were negative by PCR. These results suggest that the primer pair may be useful for identification of the species belonging to the subgenus Leishmania of the New World as well as to distinguish subgenus Leishmania from subgenus Viannia.

Animals↗
PubMed1998

Rapid identification of Leishmania species from formalin-fixed biopsy samples by polymorphism-specific polymerase chain reaction.

The precise identification and classification of Leishmania species is important for public health surveillance since different species cause different clinical features of the disease. A highly specific polymerase chain reaction (PCR) panel was developed to enable the identification of the five major Leishmania species that cause New World cutaneous leishmaniases. The primers used for this panel were designed to distinguish the polymorphism in sequences of commonly amplified DNA bands of the parasites produced by arbitrarily primed PCR. These polymorphism-specific PCR diagnoses were performed with formalin-fixed biopsy specimens of the leishmanial lesions from four patients in Ecuador and one hamster skin lesion, and these lesions were determined to be caused by Leishmania (Viannia) panamensis, L. (Leishmania) mexicana, and L. (L.) amazonensis. The PCR panel may offer an important and practical approach to the standardized identification of Leishmania species in field examinations.

Animals↗
PubMed1998

A preliminary study aimed at the detection of Leishmania parasites in subjects with cutaneous leishmaniasis using polymerase chain reaction.

As a basic study for future diagnosis of cutaneous leishmaniasis, we tried to detect Leishmania parasites representing different species in the subgenera Leishmania and Viannia from subject patients with cutaneous leishmaniasis by using the polymerase chain reaction (PCR) with the subgenus Viannia specific primer. Four out of the 14 specimens revealed an amplified DNA of 70 bp specific for the subgenus Viannia (L. braziliensis complex). No bands were detected in the rest of the specimens belonging to the subgenus Leishmania and unclassified groups. The base sequences of the amplified DNA corresponded with those of the L. (V). braziliensis kinetoplast minicircle. We concluded that PCR using the present primer specific for the subgenus Viannia would be useful in detecting Leishmania parasites in lesions of cutaneous leishmaniasis caused by the L. braziliensis complex.

Animals↗
PubMed1994

Histopathological and electron microscopical features of skin lesions in a patient with bartonellosis (verruga peruana).

Chronic verruga nodules taken from a patient with Bartonellosis (verruga peruana) were studied. Histologically, specimens of all the verruga nodules had features consistent with granulomatous lesions with extensive infiltration of various types of cells along with the proliferation of capillaries. The sections were predominantly infiltrated with neutrophils and endothelial cells; histiocytes, plasma cells, lymphocytes and mast cells were also visible to some extent. The blood vessels were dilated, and many rounded and swollen endothelial cells were located peripherally; a huge number of neutrophils invaded the vessels. Electron microscopically, large number of organisms were seen in different stages of the life cycle in the stroma. Furthermore, organisms were regularly seen either in close contact or existing inside the cytoplasm of neutrophils, suggesting the phagocytic role of these cells. No organism was found inside any endothelial cells or histiocytes.

Bartonella Infections↗
PubMed1994

The use of psychotropic drugs to treat anxiety in the elderly.

Great care in prescribing and monitoring psychotropic medications for elderly patients must be taken because of their increased sensitivity to toxic side effects; their decreased physical resiliency, as compared to younger patients; and the risk of dependency and withdrawal when taking psychotropic medication. Psychosocial and psychotherapeutic interventions should be administered concurrently if pharmacotherapy is needed. When psychotropic medication is called for, the agent of choice should be that which results in the least amount of autonomic nervous system toxicity and sedation. Short half-life benzodiazepines in low doses are generally the best options for elderly patients in need of psychotropic medication. Unlike benzodiazepines with longer half-lives, they cause no metabolite accumulation and have a lower potential for toxicity.

Aged↗
PubMed1993

Depression in the elderly.

1. Depression in the elderly is a major health concern that can be life threatening if not recognized and treated. An untreated depression may result in needless suffering, institutionalization, and suicide. Lack of treatment may occur because the signs and symptoms of depression in the elderly are different from those in the young, and because depressive symptoms may be viewed by the older person, the family, and the physician as a normal part of aging. 2. Depression can occur secondarily to physical illness. Because physical illnesses occur frequently in the older population, the combination of physical illness and depression is common. 3. Through noninvasive procedures, such as positron emission tomography (PET), a greater understanding of depression will be achieved that will result in development of more specific and effective treatment. Accurate and early diagnosis and adequate treatment favor a good prognosis.

Aged↗
PubMed1993

Molecular karyotype characterization of Leishmania panamensis, Leishmania mexicana, and Leishmania major-like parasites: agents of cutaneous leishmaniasis in Ecuador.

Molecular karyotypes of Leishmania isolates from patients with cutaneous leishmaniasis in Ecuador were analyzed by pulsed-field gel electrophoresis (PFGE) and Southern blot hybridization. The DNA karyotypes of L. major-like parasites were similar between two human isolates from a lowland coastal and a highland Andean region, but were apparently different from those of eleven World Health Organization reference strains including L. major. The smallest chromosome of 240 kilobases in L. major-like parasites was found to belong to the 715-class of small linear chromosomal DNAs, which have been shown to appear in some lines of Leishmania. Chromosome banding patterns of L. mexicana isolates exhibited a novel, ordered, chromosomal ladder, and were identical among four human isolates and one canine isolate from a restricted geographic region in the Andes. On the other hand, minor chromosome size polymorphisms were observed among three L. panamensis isolates from different endemic regions near the Pacific Coast. Chromosomal locations of dihydrofolate reductase-thymidylate synthetase and P-glycoprotein genes revealed further differences in chromosomal organizations among these Leishmania species in Ecuador. These results indicate that karyotype analysis by PFGE is useful for epidemiologic studies of leishmaniasis in Ecuador.

Animals↗
PubMed1992

The use of antidepressants with elderly patients.

If we are to prevent treatment failures, we should eliminate the schism between psychosocial and biological treatments. Most depressed patients require both psychosocial and biological treatments. The patient who responds to biological treatment but does not make appropriate corrections regarding current environmental factors is at an increased risk for relapse. A strong support system can have an important preventive effect without the risks involved in long-term medication maintenance therapy. After a correct diagnosis of a major depressive disorder is made in elderly patients, the dosage of antidepressants should only be about half of the standard adult dose. Preference should be given to those antidepressants with a therapeutic profile appropriate to each particular patient. The antidepressant should have few side effects. Although antidepressant drugs are effective in treating depression, their demonstrable efficacy is surprisingly limited. Because of suicide risk and physical illnesses, older patients are more likely to require electroconvulsive therapy than younger patients. The presence of somatic delusion is a good predictor of positive response. Newer antidepressants have not been proven more effective than the older agents, such as imipramine or amitriptyline, in treating mild or severe depressions. However, they have fewer or varied side effects and therefore they are better tolerated by elderly patients (Figure 6). The consideration of side effects is a major determinant in choosing an antidepressant for a specific elderly patient. Research into the effectiveness of antidepressants has been limited by the existence of heterogeneous groups of depression and by the different therapeutic responses.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidepressive Agents↗
PubMed1991

Chronic schizophrenia: the major mental health problem of the century.

Research now shows that schizophrenia is a disease of the brain as well as the mind and, as such, must be treated in ways other than by drugs alone. Psychopharmacology is helpful in controlling the positive symptoms, but does not eliminate aspects of the disease such as apathy and withdrawal. Studies show the structure and blood flow of the schizophrenic brain is very different from the normal brain. Families of schizophrenic individuals are forming support groups to share their feelings of suddenly being cast in the role of caregivers. Additionally, the schizophrenic individual needs to be placed in a comfortable social and vocational setting to increase the chance of improvement.

Family↗
PubMed1991

Andean leishmaniasis in Ecuador caused by infection with Leishmania mexicana and L. major-like parasites.

Between 1986 and 1988, epidemiologic studies were carried out in a small rural community in an Andean region of Ecuador, where cutaneous leishmaniasis is highly endemic. A total of 25 human cases, positive for Leishmania parasites by culture and/or smear, were examined. Fourteen of the cases were in infants less than one year of age, suggesting intradomiciliary transmission of the disease. Clinically, many of these cases were similar to descriptions of "uta," a form of cutaneous leishmaniasis which occurs in Andean regions of Peru and is reported caused by L. peruviana. Of the 11 positive cultures obtained from human cases in the present study, eight were identified by molecular characterization as L. mexicana and three were identified as L. major-like. Two additional isolates of L. mexicana were also made from an infected dog and from a sand fly, Lutzomyia ayacuchensis, living in the region, thus implicating the latter species as possible reservoir and vector, respectively, of L. mexicana in this highland community. The significance and validity of recent isolates of L. major-like parasites from the New World are also discussed.

Animals↗