PubMed Health⌕ Search

Biomedical subjects

A Villena

Publications and source records attributed to A Villena.

At least 19 recordsLinked to original sources

HLA genes in Lamas Peruvian-Amazonian Amerindians.

The Lamas Amerindians are the Chancas descents who established before 1532 a.d. (Spanish conquest) at Lamas City, Wayku quarter in a Peruvian-Amazonian province (San Martin). The Lamas HLA profile shows significant differences with other Amerindians HLA profile, i.e.: (a) a higher number of newly found haplotypes compared to other studied Amerindian populations, particularly HLA-A*02-B*48-DRB1*0403-DQB1*0302, A*02-B*48-DRB1*0804-DQB1*0402 and A*02-B*40-DRB1*0407-DQB1*0302; (b) a relative high frequency of HLA-DRB1*0901 (a high frequency southern Asian allele) and HLA-B*48 (a Na-Dene, Siberian and Eskimo allele); both alleles are also found frequently in Quechuas and Aymaras, but not in many other (particularly Meso American) Amerindians and (c) correspondence and neighbor-joining dendrogram analyses show that Lamas (Chancas) may have an origin close to Amazonian Indians that later reached the Andean altiplano.

Alleles↗

Potential use of a Yersinia ruckeri O1 auxotrophic aroA mutant as a live attenuated vaccine.

The aroA gene of Yersinia ruckeri, which encodes 5-enolpyruvylshikimate 3-phosphate synthase, was insertionally inactivated with a DNA fragment containing a kanamycin resistance determinant and reintroduced by allelic exchange into the chromosome of Y. ruckeri 21102 O1 by means of the suicide vector pIVET8. The Y. ruckeri aroA::Kan(r) mutant was highly attenuated when inoculated intraperitoneally into rainbow trout, with a 50% lethal dose of >5 x 10(7) CFU. The mutants were not recoverable from the internal organs 48 h post-inoculation or later. The vaccination of rainbow trout with the AroA mutant as a live vaccine conferred significant protection (relative percentage survival = 90%) against the pathogenic wild-type strain of Y. ruckeri.

Animals↗

Effects of a non-selective beta-blocker on adult rat anterograde axonal transport and retinal ganglion layer after increased intraocular pressure.

The aim of this study was to examine the effects of timolol in an experimental model of elevated intraocular pressure (IOP). Three episcleral veins of rats with normal IOP were cauterized. Three months later we examined the effects on anterograde axonal transport from the retinal ganglion cells (RGCs) to the superior colliculus (SC) as well as on the number of neurons in the retinal ganglion layer (RGL). These parameters were also studied in a group of rats submitted to treatment with timolol after confirming that their IOP was still raised after two weeks. After the surgical procedure, the mean IOP of the experimental eyes increased to 33.5+/-1.06 mmHg (1.25 fold compared to the control group) and three months later the IOP remained significantly elevated; however, after a long period of treatment with timolol the IOP was 14.05+/-0.81 mmHg, similar to that of the control group. In the group with normal IOP, labelling with horseradish rabbit peroxidase (HRP) at 120 minutes and 24 hours postinjection showed continuous staining from the retina to the SC. In the experimental group the optic nerve head (ONH) was completely negative, although in the group treated with timolol there was partial block of axonal transport in the ONH, in which the staining was slightly more intense. The number of neurons in the RGL, counted by immunohistochemical labelling with Neu-N, showed that in eyes with normal and elevated IOP there were 423+/-11 neurons/mm(2) and 283+/-10 neurons/mm(2), respectively. After treatment with timolol the number of neurons (331+/-10 cells/mm(2) increased compared with elevated IOP eyes, although the number did not reach that of the control group. These results indicate that treatment with timolol, started two weeks after the surgical procedure, was partially neuroprotective because the loss of neurons in the RGL was lower than in untreated animals, though not sufficient to re-establish normal axonal transport.

Adrenergic beta-Antagonists↗

Ultrastructural and quantitative age-related changes in capillaries of the dorsal lateral geniculate nucleus.

An ultrastructural and quantitative study of age-related changes in the capillaries of the dorsal lateral geniculate nucleus was carried out using male Wistar rats aged 3, 24, and 28 months. The most important structural changes were found in the basal lamina: thickenings either homogeneously distributed or in specific points; spurs towards the astrocyte sheath; and osmiophilic membrane-like inclusions located within the basal lamina. Endothelial cells and pericytes showed an increase in inclusions and dense bodies in the cytoplasm. The quantitative study showed that the most pronounced alteration was the thickening of the basal lamina, which existed at 24 months. Later, at 28 months, thinning of the endothelial cells was observed together with an increase in mitochondria size and the number of pinocytic vesicles. These changes could be an endothelial cell response to compensate for the increasing transport difficulties caused by the thickening of the basal lamina. The progressive age-related changes observed in the structure of the capillaries might have an effect on the regulation of blood and brain tissue exchanges, and thus might contribute to the development of degenerative alterations in surrounding aging neurones.

Age Factors↗

Correlation between production of acyl homoserine lactones and proteases in an Aeromonas hydrophila aroA live vaccine.

Aeromonas hydrophila is a pathogen that causes disease in a wide range of homeothermic and poikilothermic hosts due to its multifactorial virulence. We have previously described the characterisation and use of an auxotrophic aroA mutant of the A. hydrophila AG2 strain as a live attenuated vaccine against A. hydrophila infections in rainbow trout (Oncorhynchus mykiss). In this study we report the expression of extracellular proteolytic activities and of quorum-sensing molecules by this mutant grown under different culture conditions, and in vaccine inocula. The aroA strain expresses extracellular proteases efficiently during in vitro growth and this ability is retained in vaccine inocula that were prepared by washing the bacterial cultures and resuspending the cells in phosphate-buffered saline. Since proteases are considered to be major bacterial antigens, the expression of these enzymes in the live attenuated vaccine may contribute to the superior protection afforded by these kind of vaccines. On the other hand, the production of serine- and metalloprotease activities in A. hydrophila has been described as controlled in a cell density-dependent fashion, through a mechanism known as quorum sensing. A microtiter method was developed that allowed correlation of the production of quorum-sensing molecules and of proteases produced by the aroA strain during in vitro growth and in the vaccine inocula. The production of both products was related to the type of culture medium and conditions used to grow the aroA mutant, whereas there was no correlation between the concentration of acyl homoserine lactones and protease production.

4-Butyrolactone↗

Impression cytology of the conjunctival epithelium after antiglaucomatous treatment with latanoprost.

PURPOSE: To study nongoblet and goblet epithelial conjunctival cells after several treatment periods with latanoprost, a prostaglandin analogue. METHODS: Twelve patients (20 eyes) were studied before the onset of treatment and after 1, 3, and 6 months of latanoprost use. Impression cytology was carried out to analyze cellular density and morphologic parameters such as minimum and maximum diameter and area. RESULTS: Nongoblet epithelium cell density did not change over the treatment period. The density of goblet cells increased after 1 month of use, but returned to initial cell density after longer treatment periods. Nongoblet epithelial cells underwent a significant reduction in size after 1, 3, and 6 months of treatment. In addition, the minimum/maximum diameter ratio suggested that after 1 month there were some changes in shape (a slight elongation) when compared to cells of untreated patients. Nevertheless, after longer treatment periods, the cells regained their original shape. No changes in size were observed in goblet cells, except for a slight decrease in maximum diameter after 6 months of treatment, which suggests that the cells became more rounded. CONCLUSIONS: The density of nongoblet epithelial cells does not change after different treatment periods with latanoprost. However, their size decreases and after short treatment periods their shape also undergoes changes. The density of goblet cells increases after 1 month of treatment, but decreases again after longer periods. Their size does not undergo any modification, although there is a variation in shape after 6 months of treatment.

Antihypertensive Agents↗

Effect of Lepidium meyenii (Maca), a root with aphrodisiac and fertility-enhancing properties, on serum reproductive hormone levels in adult healthy men.

Lepidium meyenii (Maca) is a Peruvian hypocotyl that grows exclusively between 4000 and 4500 m in the central Andes. Maca is traditionally employed in the Andean region for its supposed aphrodisiac and/or fertility-enhancing properties. This study was a 12-week double-blind, placebo-controlled, randomized, parallel trial in which active treatment with different doses of Maca Gelatinizada was compared with a placebo. The study aimed to test the hypothesis that Maca has no effect on serum reproductive hormone levels in apparently healthy men when administered in doses used for aphrodisiac and/or fertility-enhancing properties. Men aged between 21 and 56 Years received 1500 mg or 3000 mg Maca. Serum levels of luteinizing hormone, follicle-stimulating hormone, prolactin, 17-alpha hydroxyprogesterone, testosterone and 17-beta estradiol were measured before and at 2, 4, 8 and 12 weeks of treatment with placebo or Maca (1.5 g or 3.0 g per day). Data showed that compared with placebo Maca had no effect on any of the hormones studied nor did the hormones show any changes over time. Multiple regression analysis showed that serum testosterone levels were not affected by treatment with Maca at any of the times studied (P, not significant). In conclusion, treatment with Maca does not affect serum reproductive hormone levels.

17-alpha-Hydroxyprogesterone↗

Effect of Lepidium meyenii (MACA) on sexual desire and its absent relationship with serum testosterone levels in adult healthy men.

This study was a 12-week double blind placebo-controlled, randomized, parallel trial in which active treatment with different doses of Maca Gelatinizada was compared with placebo. The study aimed to demonstrate if effect of Maca on subjective report of sexual desire was because of effect on mood or serum testosterone levels. Men aged 21-56 years received Maca in one of two doses: 1,500 mg or 3,000 mg or placebo. Self-perception on sexual desire, score for Hamilton test for depression, and Hamilton test for anxiety were measured at 4, 8 and 12 weeks of treatment. An improvement in sexual desire was observed with Maca since 8 weeks of treatment. Serum testosterone and oestradiol levels were not different in men treated with Maca and in those treated with placebo (P:NS). Logistic regression analysis showed that Maca has an independent effect on sexual desire at 8 and 12 weeks of treatment, and this effect is not because of changes in either Hamilton scores for depression or anxiety or serum testosterone and oestradiol levels. In conclusion, treatment with Maca improved sexual desire.

Adult↗

Adrenopause or decline of serum adrenal androgens with age in women living at sea level or at high altitude.

The present study aimed to determine adrenopause or reduction of serum adrenal androgens with age at high altitude and at sea level. It was a cross-sectional study performed in 210 women resident at high altitude (4340 m) and 123 women living in Lima (150 m), aged 20-70 years. Fasting early morning blood samples were obtained. Serum dehydroepiandrosterone (DHEA), DHEA sulphate (DHEAS), androstenedione, testosterone and estradiol were measured by radioimmunoassay. Serum testosterone concentrations were greater in women living at high altitude than in those resident at sea level. Serum concentrations of DHEA, DHEAS and androstenedione were lower in women living at high altitude than in those living at sea level. The DHEAS/DHEA ratio was significantly greater, and the androstenedione/testosterone ratio was lower in samples from women living at high altitude. Among women older than 50 years of age, a greater decline in serum concentrations of DHEA was observed in those living at high altitude than in those living at sea level. Among women 60-70 years of age, serum concentrations of DHEA at high altitude were 46.9% of those in women of the same age living at sea level. Decay of DHEAS at sea level and at high altitude occurred from the age of 40 years. The decline was faster at high altitude than at sea level, and in women aged 60-70 years serum values of DHEAS at high altitude were 56% of those at sea level. In the same age group, serum concentrations of androstenedione among those native to high altitudes were 27.34% of the value at sea level. At sea level, serum testosterone concentrations did not change with age from 20 to 70 years. In women aged 20-39 years and 50-59 years, serum testosterone concentrations were greater at high altitude than at sea level (P<0.05). In those aged 60-70 years, the concentrations were similar in those living at sea level and at high altitude. At sea level and at high altitude, the serum testosterone/estradiol ratio increased with age (P<0.0034 and P<0.0001 respectively). This ratio increased at an earlier age among those living at high altitude (40-49 years) than among those living at sea level (50-59 years). Multivariate analysis showed that altitude (P<0.0001) and greater chronological age (P<0.001) were associated with lower serum DHEAS concentrations. DHEAS was related to chronological age (P<0.0001). Low serum androstenedione concentrations were related to living at high altitude at birth and greater chronological age (P<0.0001). In conclusion, adrenopause is attained earlier and is of greater magnitude at high altitude than at sea level.

Adrenal Glands↗

True corrected seminal fructose level: a better marker of the function of seminal vesicles in infertile men.

This study was designed to determine if the value obtained after multiplying motile sperm concentration by seminal fructose concentration, named "true corrected fructose", correlates with sperm motility in asthenozoospermic men. Forty-two male partners in infertile couples were studied. Men were treated with 100 mg daily of clomiphene citrate for 5 days. Blood and semen samples were collected before treatment and 24 h after the end of treatment. Serum testosterone, seminal fructose and sperm motility were measured in each subject. Corrected fructose (log. sperm concentration multiplied by seminal fructose), and true corrected fructose (log. motile sperm concentration multiplied by seminal fructose) values were calculated. Prevalence of asthenozoospermia was 42.85% (18 of 42). Prevalence of hypofunction of the seminal vesicles was 9.5% using seminal fructose as a marker; 40.5% using seminal corrected fructose as a marker and 47.6% using true corrected fructose as a marker of seminal vesicle function. Regression analysis showed a better coefficient of determination between true corrected fructose and motile sperm concentration (R2=0.20, p < 0.001) than with corrected fructose (R(2)=0.05, p < 0.1) or fructose concentration (R(2)=0.006, p < 0.5). Asthenozoospermia was observed in 22.7% of subjects with normal function of the seminal vesicles, and in 65% of men with low values of true corrected fructose (z=6.02, p < 0.0001). Multivariate analysis showed that sperm motility grade 3 improved after treatment with clomiphene if true corrected fructose increased (p < 0.002). In those men whose seminal vesicle function improved after clomiphene treatment, a reduction in the prevalence of asthenozoospermia from 50 to 28.6% (z=3.10, p < 0.002) was observed whereas in those whose seminal vesicles did not respond to clomiphene the prevalence of asthenozoospermia was not reduced (z=1.05; p: NS). In conclusion, true corrected fructose measurement relates with sperm motility in cases of asthenozoospermia. Asthenozoospermia improves with clomiphene treatment if seminal vesicle function improves after treatment.

Adult↗

Lepidium meyenii (Maca) improved semen parameters in adult men.

AIM: The present study was designed to determine the effect of a 4-month oral treatment with tablets of Lepidium meyenii (Maca) on seminal analysis in nine adult normal men aged 24-44 years old. METHODS: Nine men received tablets of Maca (1500 or 3000 mg/day) for 4 months. Seminal analysis was performed according to guidelines of the World Health Organization (WHO). Serum luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (PRL), testosterone (T) and estradiol (E2) were measured before and after treatment. RESULTS: Treatment with Maca resulted in increased seminal volume, sperm count per ejaculum, motile sperm count, and sperm motility. Serum hormone levels were not modified with Maca treatment. Increase of sperm count was not related to dose of Maca. CONCLUSION: Maca improved sperm production and sperm motility by mechanisms not related to LH, FSH, PRL, T and E2.

Adult↗

Spontaneous in vitro angiogenesis in a trout pronephric stromal cell line (TPS), and in TPS-haemopoietic co-cultures.

This study describes angiogenic processes taking place in the in vitro micro-environment of a trout pronephric stroma cell line (TPS) under specific culture conditions, in which fetal calf serum, horse serum and hydrocortisone-sodium-21-hemisuccinate were used as supplements to the culture medium. When TPS cultures were kept in the same flask, i.e. without passages, for longer than 7 months, epithelioid cells differentiated into endothelial cells. Early stages of such differentiation were characterised by the presence of intracellular tubular vacuoles in clusters of neighbouring epithelioid cells. Subsequently, the endothelial cells reorganised and gave rise to microvascular structures, which branched over and into the TPS multilayers. The lining cells of the microvasculature showed typical characteristics of endothelial cells, such as ovoid or cubical shape, bundles of microfilaments and microtubules, and particularly numerous small vesicles at the apical pole, some of them fused to the plasma membrane. Similar angiogenic processes were also observed in long-term haemopoietic co-cultures formed by the TPS cell line and trout pronephric cell suspensions. Developing haemopoietic cells were observed at the basal pole of the vessels, and in the vascular lumen, where some immature cells appeared in close contact with the endothelium. These results indicate that the TPS cell line contains endothelial cell precursors, which are able to differentiate under certain culture conditions.

Animals↗

Low pulse oxygen saturation in post-menopausal women at high altitude is related to a high serum testosterone/estradiol ratio.

OBJECTIVE: The present study was designed to determine if low pulse oxygen saturation (SpO(2)) in post-menopausal women at high altitude was related to high serum testosterone/estradiol (T/E(2)) ratio. METHOD: Studies were carried out in 191 women living in Cerro de Pasco, Peru (4340 m above sea level) and in 56 women living in Lima (150 m asl). Body weight, height, SpO(2), hematocrit, serum follicle stimulating hormone (FSH), T and E(2) levels were measured in all women. Body mass index (BMI), menopausal status and serum T/E(2) ratio were calculated from data. RESULT: At high altitude, the values of SpO(2), serum T, and serum E(2) were significantly lower in post-menopausal than in pre-menopausal women. Hematocrit, serum FSH levels, and serum T/E(2) ratios were significantly higher in post-menopausal women. Serum T and E(2) levels, T/E(2) ratio, SpO(2), and hematocrit levels were not further changed with time after menopause. Women with SpO(2)<85% had lower serum E(2), a higher serum T/E(2) ratio, and higher hematocrit values than women with SpO(2)>90%. At high altitude, multiple regression analysis showed that low SpO(2) was related to menopausal status (-2.6+/-0.83; beta+/-S.E.; P<0.002) and not to chronological age (-0.06+/-0.04; P: NS). Further analysis showed that low SpO(2) was related to high basal serum FSH levels and a high serum T/E(2) ratio in the presence of an interaction between FSH and T/E(2). CONCLUSION: Low values of SpO(2) in women at high altitude were related to a high T/E(2) ratio.

Adult↗

Stereological age-related changes in neurons of the rat dorsal lateral geniculate nucleus.

Quantitative methods were used to compare the changes taking place in the volume of the dorsal lateral geniculate nucleus (dLGN) and corresponding neurons of young, adult and old rats. The study was carried out on male albino rats aged 3, 18, 24 and 28 months. In order to estimate the volume of the dLGN, neuronal volume density, numerical density and total number of neurons, we used serial sections stained according to the Klüver-Barrera technique and stereological methods. We found that dorsal lateral geniculate nucleus volume increases between 3 and 28 months, with a larger increase between 24 and 28 months. Neuronal volume density and numerical density of neurons are greater at 3 months and undergo a significant decrease between 24 and 28 months. Finally, the total number of neurons is shown to be smaller in adult and old animals than in younger ones, even though no significant variations are found between 18 and 28 months. Furthermore, this study confirms the need to analyze the total number of neurons and not just neuronal density if we want to correctly evaluate some of the microscopic changes occurring during senescence.

Aging↗

Use of clomiphene citrate in the treatment of men with high sperm chromatin stability.

OBJECTIVE: To determine whether improvements of the seminal vesicle function after a 5-day course with clomiphene citrate (CC) may reduce the prevalence of men with high sperm chromatin stability under conditions of sodium dodecyl sulfate (SDS)-ethylenediaminetetraacetic acid (EDTA). DESIGN: A prospective study. SETTING: Andrology laboratory at the Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia, Lima, Peru. PATIENT(S): Forty-one male partners of infertile couples attending the andrology laboratory. INTERVENTION(S): Clomiphene citrate was administered orally twice a day. Men were treated with CC at 100 mg daily for 5 days. Blood and semen samples were collected before treatment and 24 hours after the last administration. MAIN OUTCOME MEASURE(S): Serum testosterone, seminal fructose, sperm motility, sperm chromatin stability after SDS and EDTA, and prevalence of high sperm chromatin stability. RESULT(S): The percentage of stable sperm after SDS-EDTA correlated inversely with the basal corrected concentration of seminal fructose (-1.77 +/- 0.89, beta +/- SE). High sperm chromatin stability was observed in 53.8% of the study population and in 66.7% of patients with hypofunction of the seminal vesicles. In those men whose seminal vesicle function improved after treatment with CC, the prevalence of high sperm chromatin stability was reduced from 67% to 25% (chi2 = 5.34). Logistic regression analysis showed that the higher the basal corrected seminal fructose levels and the higher the basal serum testosterone levels, the lower the probability of nonresponse of the sperm chromatin stability to treatment with CC (0.54 +/- 0.15, odds ratio +/- SE for corrected fructose; and 0.50 +/- 0.15, odds ratio +/- SE for serum testosterone). CONCLUSION(S): Hypofunction of the seminal vesicles was associated with high sperm chromatin stability, and this high sperm chromatin stability under SDS-EDTA conditions may be reduced by treatment with CC.

Adolescent↗

Relation between RNA content and ageing in neurons of the dorsal lateral geniculate nucleus.

We carried out a study to establish ribonucleic acid (RNA) content in the nucleus and cytoplasm of single neuronal cells from the dorsal lateral geniculate nucleus (dLGN) of 3-30 month-old rats. Mean RNA content was calculated as the product of RNA concentration and nuclear or cytoplasmic surface. The analysis of neuronal nuclei revealed no significant differences in RNA concentration, nuclear area, and RNA content from 3-18 months. However, a significant decrease in RNA concentration (18.73%) was found from the 18th-24th month, although no changes were observed in nuclear area and RNA content. The oldest rats, 24-30 months old, presented a significant increase in nuclear area and RNA content. As regards to the neuronal cytoplasm, no significant differences were found in any of the parameters at the ages from 3-18 months and 18-24 months. In contrast, a significant increase in RNA concentration (26.26%), cytoplasm area (18%), and RNA content (52%) takes place from the 24th-30th month. The increase in RNA content could be related to neuronal hypertrophy.

Aging↗

[Prevalence of anemia in pregnancy, Pucallpa Regional Hospital, Perú].

Population based health surveys in Peru show that the general fertility rates, proportion of pregnant adolescents, and maternal and child morbidity are higher in the jungle regions than in other parts of the country. Endemic intestinal parasitic diseases increase the risk of anemia in pregnant women already suffering from iron, folic acid, and other nutritional deficiencies. This is the most common complication of pregnancy in many Latin American countries and is often associated with premature labor, low birthweight, and perinatal mortality. There are very few studies on this subject based on jungle populations and no reliable estimates of the prevalence of anemia in local pregnant women. The present study was designed to determine the prevalence of anemia in pregnant women attending the Regional Hospital in Pucallpa, located in the Peruvian jungle, from January 1993 to June 1995. This cross-sectional study, which was based on the registries of prenatal and childbirth services encompassing 1,015 pregnant women, looked into the potential association between anemia and such variables as the mother's chronological age, schooling, previous pregnancies, and weight at the beginning of pregnancy. Maternal hemoglobin levels were compared with the newborns' weight at birth. The prevalence of anemia in this population sample was 70.1%. This value was not modified when adjusted for maternal age, schooling, or interval between births. Anemia prevalence was directly related to the number of previous pregnancies and inversely related to weight gain during pregnancy. The perinatal mortality rate was 37.7 per 1,000 births. Neither this rate nor the birthweights were associated with the mother's degree of anemia. A multivariate regression analysis showed that maternal body weight at the start of pregnancy (P = 0.0001), weight gain during pregnancy (P = 0.0001), and the number of pregnancies (P = 0.008) are predictors of birthweight. Results showed that the high prevalence of anemia in Pucallpa's pregnant women is not associated with low birthweight or a high perinatal mortality rate. Future studies should investigate the principal causes of anemia in the pregnant women of Pucallpa and how the disease affects the psychomotor development of their offspring.

Adolescent↗

The effect of ageing on RNA content in neurons from the thalamic reticular nucleus visual sector.

In this paper we investigate nucleic acid content in neurons from the dorsocaudal region of the thalamic reticular nucleus in ageing Wistar rats. Nucleic acid per surface unit was analysed by calculating mean extinction using cytophotometric methods. Once the mean extinction and nuclear and cytoplasmic areas were known, nucleic acid total content was calculated. There was an increase in nucleic acid total content and in nuclear and cytoplasmic areas from the age of 3 months onwards. We interpreted these findings as a compensatory response, by 'neuronal hypertrophy', to the deterioration process occurring in the ageing rats. Between the 24th and 30th month, i.e. old age, nucleic acid per surface unit and total content in the cytoplasm exhibited a considerable decrease.

Aging↗