Chronic hypobaric hypoxia diminishes the expression of base excision repair OGG1 enzymes in spermatozoa.

Hypobaric hypoxia induces DNA damage in rat testicular cells, the production of defective spermatozoids and decreased sperm count, associated with an increase in oxidative stress. 8-Oxoguanine glycosylase (OGG1) enzymes are main members of the base excision repair (BER) system, a DNA repair mechanism. We determined the expression levels of mitochondrial and nuclear OGG1 isoforms in spermatozoa collected from cauda epididymis in rats exposed to chronic hypobaric hypoxia (CHH) for 5, 15 and 30 days. CHH attenuates OGG1 expression in a time-dependent fashion, with a greater reduction in the mitochondrial isoform OGG1-2a (p < .05). Attenuation of the BER system may contribute to DNA damage under hypoxia exposure.

Male reproductive system and antioxidants in oxidative stress induced by hypobaric hypoxia.

In Chile, due to the intensive activity developed in confining areas of the Andes Mountains ranging in altitude over 4000 asl, there has been an increasing intermittent movement of human resources to high altitude conditions. This unusual condition, defined as hypobaric hypoxia, affects notoriously in any living organism and there shows a series of physiological responses. Studies performed in rats under chronic hypobaric hypoxia and intermittent hypobaric hypoxia have registered changes in testicular morphology together with loss of spermatogenic cells in all stages of spermatogenic cycle. Furthermore, recent tests reinforced the existence of an oxidative metabolism in epididymis of rats subjected to hypobaric hypoxia due to the increase in the regulator enzyme expression of reactive oxygen species (ROS), This increase in the production of ROS induced a rise in apoptosis at germinal cell level, leading to a state of hypo-spermatogenesis that may jeopardise masculine fertility. Therefore, the eventual development of oxidative stress in spermatogenic cells and consequently the spermatozoids of workers subjected to high altitude, either chronic or intermittent, turns out to be critical when it poses as an imminent risk to the viability and quality of the reproductive cells of workers subjected to intermittent hypobaric hypoxia.

Blueberries prevent the effect of intermittent hypobaric hypoxia in rat epididymis.

Intermittent hypobaric hypoxia (IHH) induced a decrease in sperm count and oxidative damage in epididymis. We have previously demonstrated that a blueberry-enriched polyphenol extract (BB-4) reduced the adverse effects of oxidative stress in rat testis under hypobaric hypoxia. The aim of this study was to evaluate whether BB-4 could reverse oxidative stress in epididymis. To evaluate the protective role of BB-4 in epididymis, male rats were exposed to IHH. Lipid peroxidation, (LPO) expression and activity of glutathione reductase (GR) were evaluated. Our results showed a reduction in LPO and a decrease in GR activity in rat epididymis exposed to IHH. These results suggest that BB-4 can prevent the effects of IHH in rat epididymis.

Effect of Pesticides on Peroxisome Proliferator-Activated Receptors (PPARs) and Their Association with Obesity and Diabetes.

Obesity and diabetes mellitus are considered the most important diseases of the XXI century. Recently, many epidemiological studies have linked exposure to pesticides to the development of obesity and type 2 diabetes mellitus. The role of pesticides and their possible influence on the development of these diseases was investigated by examining the relationship between these compounds and one of the major nuclear receptor families controlling lipid and carbohydrate metabolism: the peroxisome proliferator-activated receptors (PPARs), PPARα, PPARß/δ, and PPARγ; this was possible through in silico, in vitro, and in vivo assays. The present review aims to show the effect of pesticides on PPARs and their contribution to the changes in energy metabolism that enable the development of obesity and type 2 diabetes mellitus.

Hemagglutinating activity of Gallibacterium strains.

In the present study, the hemagglutinating activity of seven reference strains, and nine Mexican and three Danish field isolates, of Gallibacterium was investigated by using fresh erythrocytes of 19 different types including chicken (broiler, rooster, layer hen), turkey, pigeon, quail, duck, Harris's hawk (Parabuteo unicinctus), house finch (Carpodacus mexicanus), cow, sheep, horse, dog, rabbit, pig, and human (groups A, B, AB, and O; Rh+). Agglutination was observed for broiler chicken, layer hen, quail, rabbit, and pig erythrocytes with a subset of Gallibacterium strains, whereas most tested strains agglutinated rabbit erythrocytes. Transmission electron microscopic examination of a hemagglutinating strain demonstrated a close interaction between the bacterial and erythrocyte surfaces. The results indicate that some Gallibacterium strains are able to agglutinate avian or mammalian erythrocytes, or both. However, the mechanisms enabling hemagglutination are not known and will be addressed in future studies.

Batch nitrifying cultures in presence of mixtures of benzene, toluene, and m-xylene.

Benzene, toluene, and m-xylene compounds in individual (5.0 +/- 0.5 mg C l(-1)) and mixed solutions (2.5 +/- 0.2 mg C l(-1) for each one) in nitrifying batch cultures induced a decrease in the specific rates of NH4+ consumption (81 +/- 6%) and NO3- production (39-79%). However, after 24 h, ammonium consumption efficiency and conversion of consumed NH4+ -N into NO3- -N were close to 100% and there was no significant accumulation of nitrite in the medium. After 24 h, no aromatic intermediate was detected in the cultures and 50% of the mixed compounds was converted to acetate. The following order of biotransformation was found: m-xylene > toluene > benzene. Transformation rate of m-xylene was 0.051 +/- 0.005 g C (g protein-N h)(-1) in individual and mixed solutions. When m-xylene was added, benzene was oxidized at a faster rate (0.051 +/- 0.005 g C (g protein-N h)(-1)) whereas toluene at a slower rate (0.012 +/- 0.002 g C (g protein-N h)(-1)).

KIR gene in ethnic and Mestizo populations from Mexico.

Killer cell immunoglobulin-like receptors are characterized by their great diversity of genes and alleles. Population studies have identified the presence of a broad variety of genotypes. In Mexico, there are diverse ethnic groups representing 9% of the total population and the rest is composed of Mestizos with a more varied biology. For the purpose of this study, genotyping was performed in Mestizos, in Mexico City inhabitants, and in three ethnic groups. The frequencies of genes KIR2DL2, 2DL5, 2DS1-3, 2DS5, and 3DS1 showed a greater variability in the groups studied. A total of 12 different genotypes were identified, the higher number for the Mestizos and the lower number for the Tarahumaras. Genotype 1 was found at a greater frequency in all the groups, except for the Tarahumaras, in which genotype 4 was more frequent. The frequency of genotypes 4 and 8 in Mexicans was higher than that for other populations analyzed. By subtyping of KIR3DL1, 3DL2, 2DL1, and 2DL3, two B haplotypes were identified in families; both were absent in Caucasian families. Our results indicated a greater diversity of genes in the Mestizos group than in the ethnic groups.

Kinetic and metabolic study of benzene, toluene and m-xylene in nitrifying batch cultures.

The effect of benzene, toluene, and m-xylene (BTX) compounds on the nitrifying activity of a sludge produced in steady-state nitrification was evaluated in batch cultures. Benzene and m-xylene at 10 mg C/L decreased ammonium consumption efficiency by 57% and 26%, respectively, whereas toluene did not affect the ammonium oxidation process. The consumed NH4+-N was totally oxidized to NO3- -N. There was no significant effect at 5 mg C/L of each aromatic compound. BTX (5-20mg C/L) induced a significant decrease in the values for specific rates of NH4+ -N consumption (76-99%) and NO3- -N production (45-98%). At 10 mg C/L of BTX compounds, the inhibition order on nitrate production was: benzene > m-xylene > toluene while at 20 mg C/L, the sequence changed to m-xylene > toluene > benzene for both nitrification inhibition and BTX compounds persistence. At 5 mg C/L of BTX compounds, there was no toxic effect on the sludge whereas from 10 to 50 mgC/L, bacteria did not totally recover their nitrifying activity. At a concentration of 5 mg C/L, toluene was first oxidized to benzyl alcohol, which was later oxidized to butyrate while m-xylene was oxidized to acetate and butyrate.

Functional recovery from cortical hemiplegia in the rat: effects of a callosotomy.

The present work aimed at studying the participation of the homologous contralateral zone to a unilateral somatomotor cortex lesion, once the animals had showed a significant functional recovery. We studied recovery of coordinated walking after unilateral motor cortex aspiration in rats. A callosotomy was performed 20 days after the initial lesion, without significant effects. We conclude that after this time period, the intact hemisphere plays no role in the recovery process, suggesting that at this time point recovery does not depend on the integrity of corpus callosal fibers at this rostral-caudal level.

In vitro hematopoiesis in patients with malignant lymphoma during active disease and at complete clinical remission after chemotherapy.

Malignant lymphomas are neoplastic diseases of lymphoid cells, which usually originate in the lymph nodes. During the last two decades, significant progress has been made in the characterization of chromosomal and molecular alterations in these malignancies. To date, however, the composition and function of the hematopoietic system in this group of hematological disorders is still not fully understood. In the present study, we have determined the progenitor cell content in 10 patients with diffuse large-cell lymphoma (DLCL) and characterized the proliferation of these cells in long-term marrow cultures. We have also addressed some issues regarding the composition and function of the hematopoietic microenvironment in this malignancy. All the patients included in this study showed normal hematological parameters in peripheral blood, both before and after chemotherapy, however, significant hematopoietic alterations were consistently observed. As compared to normal subjects, lymphoma patients showed a 35% reduction in progenitor cell numbers, including myeloid, erythroid and multipotent progenitors. The in vitro proliferation of these cells was also deficient, since their levels in long-term marrow cultures were significantly lower than those observed in normal bone marrow cultures. Fibroblastic progenitors were reduced by >50% and this correlated with a deficient adherent cell layer development in culture. A reduction was also seen in the levels in culture supernatant of the stimulatory cytokines Stem Cell Factor and Interleukin-6. Interestingly, all the hematopoietic alterations mentioned above were still present in patients at complete clinical remission after chemotherapy. Thus, in the present study we have demonstrated significant in vitro deficiencies in the composition and function of the hematopoietic system in patients with diffuse large-cell lymphoma, both during active disease and at the time of complete clinical remission.

The influence of pulsed electrical stimulation on the wound healing of burned rat skin.

Electrostimulation of wounds caused healing to proceed in a thoroughly organized manner. A trial using rats subjected to second degree burns was conducted to evaluate, under scanning electron microscopy (SEM), the healing capabilities of skin to which an antiseptic (iodine) and referred electrical stimulation were applied. Untreated, unharmed skin was also studied as control. Images obtained using SEM revealed that only the repaired skin of the electrostimulated group had an appearance similar to that of the control skin (kappa = 1), and that the overall appearance of the repaired skin was compatible with a well organized healing process.

Benzene transformation in nitrifying batch cultures.

The effect of benzene on the nitrifying activity of a sludge produced in steady-state nitrification was evaluated in batch cultures. Benzene at 10 mg/L inhibited nitrate formation by 53%, whereas at 5 mg/L there was no inhibition. For initial benzene concentrations of 0, 7, and 10 mg/L, the specific rates of NO(3)(-)-N production were 0.545 +/- 0.101, 0.306 +/- 0.024, and 0.141 +/- 0.010 g NO(3)(-)-N/g microbial protein-N.h, respectively. The specific rates of benzene consumption at 7, 12, and 20 mg/L were 0.034 +/- 0.003, 0.050 +/- 0.006, and 0.027 +/- 0.002 g/g microbial protein-N.h, respectively. Up to a concentration of 10 mg/L, benzene was first oxidized to phenol, which was later totally oxidized to acetate. Benzene at higher concentrations (20 and 30 mg/L) was converted to intermediates other than acetate, phenol, or catechol. These results suggest that this type of nitrifying consortium coupled with a denitrification system may have promising applications for complete removal of nitrogen and benzene from wastewaters.

Clinical trial with Nestorone subdermal contraceptive implants.

The clinical performance and the in vivo release rate of a single 4-cm Nestorone subdermal implant were investigated. Implants manufactured by two different procedures were compared. Volunteers were 70 healthy women of proven fertility. Forty women provided blood samples twice a week in the pretreatment cycle and for 5-6 weeks at 6-month intervals during treatment. Additional control cycles (n = 31) were studied in 19 Copper T users. No pregnancy occurred in 1570 woman-months. Nestorone plasma levels (x +/- S.E.) declined from 112 +/- 8 to 86 +/- 3 pmol/L (Implant A) and from 145 +/- 8 to 57 +/- 5 pmol/L (Implant B) from the first to the 24th month. Progesterone levels were < 9.5 nmol/L in 166 (93%) of 178 blood samplings taken during treatment. Progesterone levels > 16 nmol/L were found in only 7 sampling periods (3.9%) in treated women and in 70 (98.6%) out of 71 control cycles. No ovulation occurred with Nestorone plasma levels above 105 pmol/L. No abnormal changes were observed in plasma lipoproteins or other clinical chemistry parameters during treatment. The implants were well tolerated. The most frequent complaint was the occurrence of irregular bleeding. Enlarged follicles found during pelvic examination in 8 subjects (11.4%) disappeared spontaneously in 10 days to 6 weeks. Implants were removed because of medical (n = 10, 14.3%) or personal reasons (n = 6, 8.6%) or at the 24th month of treatment (n = 54, 77.1%). The estimated average daily in vivo release rate of Nestorone was 45-50 micrograms/day. A single Nestorone subdermal implant affords efficient contraceptive protection during two years.

Contraceptive efficacy and clinical performance of Nestorone implants in postpartum women.

The objective of this study was to evaluate the contraceptive efficacy and clinical performance of a Nestorone subdermal implant (NES) in the postpartum period. NES (n = 100) and Copper T intrauterine device (T-Cu; n = 100) acceptors initiated contraception at 8 weeks postpartum and were followed at monthly intervals during the first year and at 3-month intervals thereafter. Pregnancy rates, breastfeeding performance, infant growth, bleeding pattern, and side effects were assessed. Blood and milk NES concentration were measured. No pregnancy occurred in 2195 and 2145 woman-months of NES implant and T-Cu use, respectively. No effect of NES on lactation and infant growth and no serious adverse events were observed. Lactational amenorrhea was significantly longer in NES users (353 +/- 20 days) than in T-Cu users (201 +/- 11 days). More NES users (55.8%) experienced prolonged bleedings than did T-Cu users (36.2%). Concentrations of NES in breast milk ranged between 54-135 pmol/liter. The Nestorone implant is a highly effective contraceptive, safe for breastfed infants because the steroid is inactive by the oral route.

Fertility regulation in nursing women. IX. Contraceptive performance, duration of lactation, infant growth, and bleeding patterns during use of progesterone vaginal rings, progestin-only pills, Norplant implants, and Copper T 380-A intrauterine devices.

This study evaluated the performance of progesterone vaginal rings (n = 187), progestin-only pills (n = 117), Norplant implants (n = 120), and Copper T 380-A intrauterine devices (n = 122) in lactating women. Contraceptive efficacy, bleeding pattern, and influence of the method upon breastfeeding duration and infant growth were compared with those of untreated women (n = 236) who relied on lactational infertility. Participants were healthy, 18 to 38 years, had had a normal delivery, and were intending to breastfeed for as long as possible. Contraceptives were initiated at day 57 +/- 3 postpartum. Results are reported for the first year of use. All methods were highly effective, with pregnancy rates below 1%. None affected breastfeeding performance or the rate of infant growth. Users of the progestin-only methods experienced a period of lactational amenorrhea 4 to 5 months longer than did users of Copper T or untreated women. More than half of the women in each contraceptive group reported a bleeding in the first month after treatment initiation, which was not considered in the calculation of the duration of amenorrhea. Prolonged or frequent bleedings were infrequent. The proportion of bleedings lasting more than 10 days ranged from 0 in the progestin-only pills group to 7% in the Norplant implants group. The four methods, initiated around the eighth postpartum week, provided effective contraception with no negative effects upon lactation or infant growth and without the bleeding problems associated with their use in nonlactating women.

Preregistration study on the safety and contraceptive efficacy of a progesterone-releasing vaginal ring in Chilean nursing women.

The contraceptive efficacy and safety of a progesterone-releasing vaginal ring (PVR) manufactured in Chile were compared to that of the Copper T 380A IUD (T-Cu) in nursing women enrolled at three Chilean clinics. A total of 285 volunteers chose to use the PVR and 262 the T-Cu. Plasma progesterone levels attained with the ring decreased from 25 to 14 nmol/L from month 1 to month 3 of use. Ring replacement was scheduled every 3 months. Volunteers continued in the study until weaning or completing the continuous use of four PVRs. No pregnancies occurred in 2320 and 2183 woman-months of exposure with the PVR and the T-Cu, respectively. Lower continuation rates in the first 6 months because of problems with use and a longer lactational amenorrhea were observed in the PVR than in the T-Cu group. Breast-feeding performance and infant growth were similar in both groups. These results confirm the high efficacy and safety of the PVR for nursing women and have led to the registration of the PVR by Chilean health authorities.

PIP: This study compares the contraceptive efficacy and safety of a progesterone-releasing vaginal ring (PVR) manufactured in Chile and a Copper T 380A IUD (T-Cu) in nursing women enrolled at three Chilean clinics. A total of 285 volunteers used the PVR and 262 used T-Cu. Plasma progesterone levels attained with the ring decreased from 25 to 14 nmol/l from month 1 to month 3 of use. Ring replacement was scheduled every 3 months. Volunteers continued in the study until weaning or completing the continuous use of 4 PVRs. There were no pregnancies in 2320 and 2183 woman-months of exposure with the PVR and the T-Cu, respectively. Lower continuation rates in the first 6 months because of problems with use and a longer lactational amenorrhea were seen in the PVR group. Breast-feeding performance and infant growth were similar in both groups. These results prove the high efficacy and safety of the PVR for nursing women. This has led to the registration of the PVR by Chilean health authorities.

Development of post-traumatic cysts in the spinal cord of rats-subjected to severe spinal cord contusion.

To study the development of post-traumatic spinal cord (SC) cysts, and their fine anatomic characteristics, rats were subjected to severe SC contusion. Specimens were analyzed from day 1 to 1 year post-injury. Using conventional light, and transmission and scanning electron microscopy, three stages were typified, namely: necrosis, repair, and stability. The final cell composition and thickness of the cyst walls were not uniform. Astrocytes, fibroblasts, ependymal cells, and collagen fibers were the main constituents. Chronic inflammatory cells were also observed. The neuropathologic characterization of posttraumatic SC cysts could be useful in planning strategies for SC reconstruction at different times post-injury.

Association of neck circumference and obesity status with elevated blood pressure in children.

High blood pressure (BP) and overweight/obesity are increasingly prevalent in children. We examined the associations of excess weight indicators including neck circumference (NC) and body mass index (BMI) with high BP in children. We hypothesized that high NC is associated with elevated BP. We utilized cross-sectional anthropometric and BP data on 1058 children aged 6-18 years. Patients were classified into weight and NC categories according to published guidelines. Prehypertension was defined as systolic or diastolic BP levels between 90th and 95th percentile for gender, age and height. Hypertension signifies systolic and/or diastolic BP levels ≥ 95th percentile for age, gender and height. The prevalence of elevated BP was 29.2% (prehypertension=10.1%, hypertension=19.1%). The prevalence of overweight and obesity was 19.0 and 18.7%, respectively. Rates of wide NC increased progressively with BMI categories by 8.8, 29.4 and 68.7% among normal weight, overweight and obese children, respectively. Within each BMI category, the unadjusted odds ratio for elevated BP was significantly higher in children with wide NC than those with normal NC (normal weight OR=1.78 (1.0-3.1), P=0.04); overweight OR=2.74 (1.5-5.2), P=0.001); obese OR=2.44 (1.3-4.6), P=0.006)). Increasing NC and BMI are associated with elevated BP in children. Joint presence of wide NC and high BMI is associated with significantly high rates of elevated BP. NC measurement may be a helpful tool to detect the presence of elevated BP in children.

Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite.

The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum) were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control.

Bacterial consortium for copper extraction from sulphide ore consisting mainly of chalcopyrite

The mining industry is looking forward for bacterial consortia for economic extraction of copper from low-grade ores. The main objective was to determine an optimal bacterial consortium from several bacterial strains to obtain copper from the leach of chalcopyrite. The major native bacterial species involved in the bioleaching of sulphide ore (Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, Leptospirillum ferrooxidans and Leptospirillum ferriphilum) were isolated and the assays were performed with individual bacteria and in combination with At. thiooxidans. In conclusion, it was found that the consortium integrated by At. ferrooxidans and At. thiooxidans removed 70% of copper in 35 days from the selected ore, showing significant differences with the other consortia, which removed only 35% of copper in 35 days. To validate the assays was done an escalation in columns, where the bacterial consortium achieved a higher percentage of copper extraction regarding to control.